UC-NRLF 


MEIMCAL 


COLLEGE  OF  PHARMACY 


COL.lt  k 
Of  PHARMAQKL 


REAGENTS  AND  REACTIONS 


Translated  from  the  Italian. 


TREATISE    ON    GENERAL    AND    INDUSTRIAL 
CHEMISTRY.     By  DR.  E.  MOLINARI. 

Vol.  I.     INORGANIC. 
Trans,  by  E.  FVLEMAN,  B.Sc. 

Vol.  II.     ORGANIC. 
Trans,  by  T.  H.  POPE,  F.I.C. 


TREATISE          ON        APPLIED         ANALYTICAL 
CHEMISTRY.     Edited  by  PROF.  V.  VILLAVKCCHIA. 
Trans,  by  T.  H.  POPE,  F.I.C. 
In  2  volumes. 

CHEMICAL    COMBINATION    AMONG    METALS. 
By  DRS.  M.  GUIA  and  C.  GUIA-LOLLINI. 
Trans,  by  G.  W.  ROBINSON. 


REAGENTS  AND  REACTIONS 


BY 

EDGARDO    TOGNOLI,    M.D. 

Professor  in  the  University  of  Modena 


Translated  from  the  Italian 

BY 
C.  AINSWORTH    MITCHELL,   B.A.,   F.I.C. 


California  College  of  Pharmacy 


PHILADELPHIA 

P.   BLAKISTON'S  SON   &  CO. 

1012   WALNUT  STREET 
1918 


Printed  in  Great  Britain. 


PREFATORY    NOTE   BY   THE 
TRANSLATOR 

IT  is  a  common  practice,  more  especially  in 
foreign  scientific  literature,  to  refer  to  a  reaction 
by  the  name  of  the  chemist  who  first  applied  it, 
although,  in  many  cases,  the  reaction  may  hardly 
be  known  outside  the  country  of  its  origin. 

It  was,  therefore,  a  good  idea  on  the  part  of 
Dr.  Tognoli  to  gather  together  in  a  convenient 
form  most  of  the  important  chemical  reactions,  so 
that  the  chemist  has  only  to  refer  to  the  alpha- 
betical list  to  refresh  his  memory  upon  the  details 
of  any  particular  test. 

Some  of  the  reactions  described  in  the  original 
are  practically  obsolete,  but  I  have  retained  them 
in  the  translation,  since  they  are  still  mentioned  in 
papers  on  the  subjects  with  which  they  are  con- 
cerned. I  have  also  added  a  number  of  the  more 
important  reactions  which  were  not  included  in  the 
Italian  edition. 

Many  of  the  tests  belong  to  the  domain   of 

-424 


PREFATORY  NOTE  BY  THE  TRANSLATOR 

physiological  chemistry,  and  might,  on  first 
thoughts,  seem  to  be  outside  the  province  of  the 
analytical  chemist ;  but  even  of  these  tests,  some 
are  mentioned  from  time  to  time  in  chemical 
journals,  and  it  would  be  difficult  to  choose  which 
should  be  omitted,  even  if  the  book  were  intended 
solely  for  the  chemist ;  whilst  they  undoubtedly 
render  the  book  of  greater  value  to  the  medical  man . 

C.   AINSWORTH   MITCHELL 

WHITE  COTTAGE, 
THE  COMMON, 

AMERSHAM 


rtt   lo 
Wi 


TABLE   OF   CONTENTS 

PAGE 

TRANSLATOR'S  PREFATORY  NOTE         .         .  v 

INTRODUCTION  AND  GENERAL  NOTES.         .  i 
TESTS  OF  PURITY  OF  THE  MORE  IMPORTANT 

REAGENTS     ......  5 

REAGENTS  AND  REACTIONS        .  54 

TEST  PAPERS    ......  193 

COLLECTIVE  INDEX  OF  REAGENTS  AND  RE- 
ACTIONS OF  DIFFERENT  SUBSTANCES        .  201 

TABLES. 

I.     INTERNATIONAL  ATOMIC  WEIGHTS  .  214 

II.    AQUEOUS  SOLUTIONS  OF  AMMONIA  .  215 

III.  AQUEOUS    SOLUTIONS    OF   CAUSTIC 

POTASH     .         .         .         .         .  216 

IV.  AQUEOUS    SOLUTIONS    OF    CAUSTIC 

SODA         .....  217 

V.     POTASSIUM  CARBONATE  AT  15°  C.  .  218 

VI.    SODIUM  CARBONATE  AT  15°  C.        .  218 

VII.     HYDROCHLORIC  ACID     .         .         .  219 

VIII.     NITRIC  ACID         ....  219 

IX.    SULPHURIC  ACID  ....  220 

vii 


TABLE   OF   CONTENTS. 

TABLES.  PAGE 

X.    SPECIFIC  GRAVITY  OF  PHOSPHORIC 
ACID  AT  15°  C.  AND  CONTENT  OF 

H8PO4  AND    P2O5  .  .  .221 

XL    SPECIFIC  GRAVITY  OF  ACETIC  ACID 

AT    15°    C 222 

XII.  METHYL  ALCOHOL          ...     223 

XIII.  ALCOHOL       ...  .     224 

XIV.  ALCOHOL       .  .  .225 
XV.  ALCOHOL       .                                    .     226 

XVI.     GLYCERIN     .  .         .     227 

XVII.     DEXTROSE  228 


vni 


REAGENTS    AND 
REACTIONS. 


INTRODUCTION. 

THE  identification  of  substances  in  chemistry 
is  effected  by  transforming  the  substance  under 
examination  into  a  new  compound  with  charac- 
teristic specific  properties,  by  means  of  a  known 
substance.  This  intermediary  substance  is  termed 
a  reagent,  and  the  transformation  effected  a 
chemical  reaction. 

A  chemical  reagent  is  used,  therefore,  in  all 
chemical  and  microscopical  investigations,  either 
for  the  identification  of  individual  elements  or 
their  compounds,  or  for  the  detection  and  quantita- 
tive estimation  of  these  substances  in  various 
mineral,  animal,  and  vegetable  complexes.  Hence 
it  plays  a  fundamental  part  in  all  the  various 
chemical  reactions  which  can  be  utilised  in  the 
numerous  methods  of  investigation  employed  in 
bromatological,  medico-legal  and  clinical  chemistry. 

Chemical  reactions  can  take  place  in  two  ways — 
the  wet  and  the  dry  way  ;  and  they  are  always 
made  manifest  by  characteristic  phenomena  such 
as  the  formation  of  a  precipitate,  the  evolution 
of  gas,  the  change  or  appearance  of  a  coloration. 

To  be  able  to  produce  a  reaction  or  make  an 
analysis  with  certainty  it  is  necessary  to  know 
definitely  not  only  the  reactions  of  individual 
substances,  but  also  the  sensitiveness  of  the  same 


REAGENTS   AND   REACTIONS. 

reactions.  It  is  therefore  advisable  to  use  reagents 
of  known  concentration,  and  always  to  employ  a 
known  quantity  of  the  different  substances.  In 
practice  it  is  best,  as  proposed  by  Blochmann,  to 
use  normal  solutions. 

By  a  normal  solution  is  understood  a  solution 
which  contains  dissolved  in  a  litre  of  water  the 
equivalent  in  grammes  of  the  respective  sub- 
stances. Hence  decinormal  and  centinormal 
solutions  contain  respectively  T^  and  T^  of  a 
gramme  equivalent  r  er  litre. 

The  reagents  required  for  various  reactions  are 
as  follows  :— 

(a)  CONCENTRATED  ACIDS. 

1.  Hydrochloric  acid   . .     specific  gravity  —  1-189 

2.  Nitric  acid    ..          ..  ,,          ,,  1*385 

3.  Sulphuric  acid          ..  ,,          ,,  1-840 

(b)  CONCENTRATED  ALKALIES. 

1.  Ammonia  . .          . .     27  per  cent,  solution. 

2.  Potassium  hydroxide    . .     35       ,, 

3.  Sodium  hydroxide         . .     35 

(c)  DILUTE  ACIDS  (DOUBLE  NORMAL). 
(In  a  litre  of  water.) 

1.  Hydrochloric  acid  . .  . .       72*94  grms. 

2.  Nitric  acid  . .  . .  . .  126-04      ,, 

3.  Sulphuric  acid      . .  . .  . .       98-09      ,, 

4.  Acetic  acid  . .  . .  . .  120-06 

5.  Oxalic  acid  . .  . .  . .  126  ,, 

6.  Tartaric  acid        . .  . .  . .  3°°*i 

(d)  DILUTE  ALKALIES  (DOUBLE  NORMAL). 
(In  a  litre  of  water.) 

1.  Ammonia  . .          . .          . .       70-10  grms. 

2.  Potassium  hydroxide      . .          . .     112-22      „ 

3.  Sodium  hydroxide  . .          . .       80-02      ,, 


INTRO 


I.  Double  Normal  Solutions. 
(In  a  litre  of  water.) 

1.  Ammonium  carbonate    . .          . .       96-08  grms. 

2.  Ammonium  chloride       . .          . .  107  ,, 

3.  Sodium  carbonate  . .          . .  106          „ 

4.  Ammonium  sulphide. 

II.  Normal  Solutions.  • 
(In  a  litre  of  water.) 

1.  Sodium  acetate  . .          . .  136-07  grms. 

2.  Disodium  phosphate     .  .          . .  119-34 

3.  Sodium  hypochlorite     . .          . .       69-01 

4.  Sodium  nitrate  . .          . .          . .       85-1 

5.  Sodium  nitrite   . .          . .          . .       69-01 

6.  Potassium  bichromate  . .       85-1 

7.  Calcium  chloride  . .          . .       49-03 

8.  Magnesium  sulphate     . .          .  .  123*25 

9.  Barium  chloride  . .          . .  122-16 

10.  Ferric  chloride   . .          . .          . .       54'o8 

11.  Potassium  ferrocyanide  . .  105-59 

12.  Lead  acetate      . .          . .          . .  189-60 

13.  Stannous  chloride         . .          . .  113 

14.  Mercurous  nitrate         . .          . .  262-01 

15.  Cobalt  nitrate    . .          . .          . .  145*54 

16.  Ammonium  oxalate      . .          . .       71-06 

III.  Seminormal  Solutions. 
(In  a  litre  of  water.) 

1.  Bismuth  nitrate  . .          . .       80-69  grms. 

2.  Mercuric  chloride  . .          . .       67-73 

3.  Sodium  thiosulphate     . .          . .  124-11 

4.  Sodium  bromide  . .          . .       69-48 

5.  Potassium  cyanide        . .          . .       32-56 

6.  Potassium  iodide  . .          . .       83-01 

7.  Potassium  thiocyanate  . .       48*54 

3  1-2 


REAGENTS   AND   REACTIONS. 


8.  Zinc  sulphate     . 

9.  Copper  sulphate 

10.  Alum 

11.  Chrome  alum 


71-89  grms. 
62-43      „ 
79-08      „ 

83-24     „ 


IV.  Decinormal  Solutions. 
(In  a  litre  of  water.) 

1.  Uranium  acetate  . .          . .       21-03  grms. 

2.  Silver  nitrate        . .          . .          . .       16-99      » 

SATURATED  SOLUTIONS. 

i.  Saturated  solution  of     4.  Saturated  solution  of 
hydrogen  sulphide.  calcium  sulphate. 

5.  Chlorine  water. 

6.  Bromine  water. 


2.  Baryta  water. 

3.  Lime  water. 


SOLVENTS. 


1.  Acetone. 

2.  Alcohol. 

3.  Amyl  alcohol. 

4.  Aniline. 

5.  Benzene. 

6.  Carbon  disulphide. 


7. 

8. 

9. 
10. 
11. 
12. 


Chloroform. 

Ether. 

Ethyl  acetate. 

Glycerin. 

Methyl  alcohol. 

Petroleum  spirit. 


TESTS    OF   PURITY. 


TESTS  OF  PURITY  OF  THE  MORE 
IMPORTANT  REAGENTS- 
ACETIC  ACID. 
C2H4O2  =  CH8COOH  =  60. 

1.  Ten  grms.   evaporated  ought    to  leave    no 
residue  (non-volatile  substances). 

2.  Ten  grms.   diluted  with  water  to   100   c.c. 
should  not  show  any  change  when  neutralised  with 
ammonia,     or    when    treated    with    ammonium 
sulphide  or  with  hydrogen  sulphide,   even  after 
standing  for  twenty-four  hours  (absence  of  heavy 
metals). 

3.  A  5  per  cent,  solution  of  acetic  acid  should 
show  no  turbidity  with  barium  chloride  (absence 
of  sulphates),  even  after  the  addition  of  chlorine 
water  (absence  of  sulphurous  anhydride). 

4.  A  5  per  cent,  solution  to  which  nitric  acid 
has  been  added  should  give  no  precipitate  with 
silver  nitrate  (absence  of  chlorides). 

5.  One  c.c.   of  the  acid  mixed  with  5  c.c.   of 
Bettendorf's  reagent  should  not  show  any  brown 
coloration  after  some  hours  (absence  of  arsenic) . 

6.  Five  c.c.  of  the  acid  diluted  with  15  c.c.  of 
water  and  treated  with  I  c.c.  of  a  o-i  per  cent, 
solution  of  potassium  permanganate  should  retain 
the  pink  colour  for  at  least  ten  minutes  (absence  of 
tarry  matter). 

7.  A  solution  of  mercuric  oxide  in  acetic  acid 
ought  to  remain  clear  when  boiled   (absence  of 
formic  acid). 

8.  It  should  dissolve  in  water,  and  the  solution 
should   not    become   turbid   on   the   addition    of 
ammonium  oxalate  (calcium  salts). 

5 


REAGENTS   AND   REACTIONS. 

9.  Quantitative  Estimation. — This  is  effected 
volumetrically  by  means  of  a  normal  solution  of 
potassium  hydroxide,  phenolphthalein  being  used 
as  indicator. 

ACETONE. 
CH3.CO.CHS  =  57-86. 

1.  Acetone  should  boil  at  56°  to  57°  C.  and  have" 
a  specific  gravity  of  0-812  at  o°  C. 

2.  When    evaporated    on    the    water-bath    it 
should  not  leave  any  residue   (absence  of  non- 
volatile substances.) 

3.  Its  reaction  should  be  neutral ;  on  evaporat- 
ing the  liquid,  neutralised  with  sodium  hydroxide 
if  acid,  taking  up  the  dry  residue  with  a  little  water, 
and  adding  a  trace  of  ferric  chloride,  no  blood-red 
coloration  should  appear  (absence  of  acetic  acid). 

4.  When  diluted  with  water  it  should  yield  a 
clear  solution  (absence  of  tarry  products),  which 
should   not    become    turbid   when    treated    with 
silver  nitrate,  in  the  cold,  or  on  heating  (absence 
of  aldehydes  and  reducing  substances). 

5.  When  shaken  with  dry  calcium  chloride  it 
should   not   give    a   moist    mixture    (absence    of 
moisture). 

6.  Quantitative  Estimation. — This  is  based  on 
the  transformation  of  the  acetone  into  iodoform 
by  means  of  iodine  and  potassium  hydroxide,  and 
gravimetric  determination  of  the  iodoform  pro- 
duced (Kraemer). 

ALCOHOL   (ETHYL  ALCOHOL). 
C2H5OH  =  46-05. 

I.  Alcohol  should  be  colourless  and  volatilise 
completely  when  heated  on  platinum  foil  (absence 
6 


TESTS 

of  non-volatile  mineral  matter) ,  and  should  remain 
colourless  after  the  addition  of  ammonia  (absence 
of  tarry  substances  and  tannin  derived  from  the 
casks) . 

2.  It  should  have  the  normal  physical  properties 
(boiling  point  and  specific  gravity) .    If  these  should 
be  higher  than  normal  the  presence  of  foreign 
substances  will  be  indicated. 

3.  It  should  not  contain  water.    This,  of  course, 
only  refers  to  absolute  alcohol.    When  completely 
anhydrous  it  should  not  cause  copper  sulphate 
which  has  been  dehydrated  to  turn  blue.     Water 
may  be  detected  in  alcohol  by  pouring  a  few  drops 
of  the  sample  on  to  the  surface  of  4  to  6  c.c.  of 
pure  benzene  in  a  test-tube.     In  the  presence  of 
water   the   liquid   becomes   turbid    (Gorgen).      A 
trace   of  water  may  be   detected  by   means  of 
calcium  carbide,  which  is  decomposed  by  water 
with  the  liberation  of  acetylene  (Vitali) . 

4.  Its  reaction  should  be  neutral  (absence  of 
acids) . 

5.  It  should  not  become  turbid  on  the  addition 
of  water  (absence  of  resinous  substances). 

6.  When    evaporated    at    a    low    temperature 
alcohol  should  not  leave  a  residue  with  the  objec- 
tionable odour  of  amyl  alcohol  (absence  of  fusil 
oil).    The  latter  is  then  best  identified  by  shaking 
50  c.c.  of  the  alcohol  with  an  equal  quantity  of 
chloroform  and  twice  the  volume  of  alcohol.     It 
should  not  leave  a  malodorous  residue  which  when 
treated  with  sulphuric  acid  turns  black,  and  when 
heated  with  sodium  acetate  and  sulphuric  acid 
emits    a    pleasant    pear-like    odour    (absence    of 
amyl  alcohol). 

7.  On  treating  10  c.c.  of  alcohol,  diluted  with 
10  c.c.  of  water,  with  i  c.c.  of  an  ammoniacal 
solution    of    silver   nitrate,    there    should    be   no 
darkening ;  nor  on  adding  to  10  c.c.  of  alcohol  i  c.c. 
of  a  10  per  cent,  solution  of  metadiaminobenzene 

7 


REAGENTS   AND   REACTIONS. 

should  a  reddish-yellow  coloration  appear  after 
five  minutes  (absence  of  aldehydes). 

8.  When  5  c.c.  of  alcohol  are  treated  with  5  c.c. 
of  pure  concentrated  sulphuric  acid  in  a  test-tube, 
in  such  a  manner  that  the  two  liquids  do  not  mix, 
no  red  coloration  or  red-coloured  ring  should  appear 
at  the  zone  of  contact  (absence  of  alcohol  prepared 
from  molasses  or  from  beetroot  sugar). 

9.  On  mixing  10  c.c.  of  alcohol  with  i  c.c.  of  a 
o-i  per  cent,  solution  of  potassium  permanganate, 
decolorisation   of   the   permanganate   should   not 
take  place  in  less  than  twenty  minutes.     Should 
decolorisation    occur   sooner,    and    more    or   less 
rapidly,   it  is  an  indication   of  the  presence   of 
aldehydes,  formic  acid  or  fusel  oil,  or  of  foreign 
organic    substances    such    as    occur   in    methyl 
alcohol. 

10.  Alcohol  should  not  become  turbid  nor  yield 
a  precipitate  when  treated  with  hydrogen  sulphide 
(heavy  metals). 

11.  On  treating  alcohol  with  10  c.c.  of  aniline 
and  2  c.c.  of  acetic  acid  no  red  coloration  should 
be  produced  (absence  of  furfural). 


ALUM  (POTASSIUM  ALUMINIUM  SULPHATE). 
K2A12(SO4)4.24H2O  -  948. 

1.  A  solution  of  alum  should  not  give  a  blue 
coloration    with   potassium    ferricyanide    (ferrous 
salts). 

2.  Potassium  hydroxide  should  not  produce  a 
white  insoluble  precipitate  in  a  solution  of  alum 
(magnesium  salts). 

3.  On  treating  the  solution  with  ammonia  in 
excess  and  filtering  the  liquid,  the  filtrate  should 
not  give  a  white  precipitate  with  hydrogen  sulphide 
(zinc  salts). 


TESTS    OF   PURITY. 

4.  When     boiled    with    potassium     hydroxide 
solution  it  should  not  emit  ammonia  (ammonium 
alum) . 

5.  The  solution  should  not  turn  brown  or  yield 
a    precipitate    with    hydrogen    sulphide     copper 
salts). 


AMMONIA. 
NH8  =  17-03. 

1.  Ammonia  solution  should  leave  no  residue 
when  evaporated  in  a  porcelain  dish  (fixed  mineral 
matter). 

2.  After  acidification  with  nitric  acid  it  should 
not  give  a  precipitate  with  silver  nitrate  (chlorides) , 
or  with  barium  chloride  (sulphates). 

3.  It  should  give  no  precipitate  with  ammonium 
oxalate  (calcium  salts). 

4.  On  treating  5  c.c.  of  ammonia  solution  with 
10  c.c.  of  clear  lime-water  and  10  c.c.  of  distilled 
water  free  from  carbon  dioxides,  it  should  yield 
a    clear    liquid    which    does    not    become   turbid 
even    when    boiled    (ammonium    carbonate    and 
carbamate). 

5.  When    treated    with    twice    its    volume    of 
strong  colourless  nitric  acid  it  should  not  give  a 
yellow    or    red    coloration    (coal-tar    derivatives 
such  as  aniline,  pyridine,  etc.). 

6.  It  should  not  give  a  turbidity  or  precipitate 
on  treatment  with  hydrogen  sulphide  (lead,  iron, 
zinc) . 

7.  Quantitative  Estimation. — Ammonia  may  be 
estimated    gravimetrically     as     platino-chloride ; 
but  it  is  preferable  to  estimate  it  volumetrically 
by  titration  with  a  normal  solution  of  oxalic  or 
sulphuric  acid,  using  methyl  orange  or  Congo  red 
as  indicator. 


REAGENTS    AND   REACTIONS. 

AMMONIUM   CARBONATE. 

(NH4)2CO3  -  96-08. 

1.  Ammonium  carbonate  should  volatilise  com- 
pletely without  leaving  a  residue  (fixed  mineral 
substance). 

2.  It  should  be  soluble  in  four  parts  of  cold 
water  (absence  of  an  excessive  amount  of  ammo- 
nium bicarbonate). 

3.  It  should  be  colourless  (not  of  a  yellow  colour) , 
and    when    ignited    should    not    leave    a    brown 
residue  (absence  of  tarry  substances). 

4.  Its  solution  should  not  darken  when  treated 
with  ammonium  sulphide  (iron),  and,  after  acidifi- 
cation with  hydrochloric  acid,  should  not  darken 
with  hydrogen  sulphide  (lead,  copper)  or  become 
turbid  with  barium  chloride  (sulphates). 

5.  After  acidification  with  nitric  acid  it  should 
not  give  a  precipitate  with  silver  nitrate  (chlorides)  ; 
nor  when  acidified  with  acetic  acid  should  it  give 
a  precipitate   with   ammonium  oxalate   (calcium 
salts). 

AMMONIUM   CHLORIDE. 
NH4C1  =  53-49- 

I.  Ammonium  chloride  should  be  colourless. 
A  yellow  coloration  may  be  due  to  the  presence 
of  iron,  whilst  a  reddish  coloration  may  be  due  to 
the  presence  of  tarry  substances  ;  in  the  latter 
case  a  filtered  aqueous  solution  of  the  salt  will  also 
be  of  a  reddish  colour.  If,  however,  ammonium 
chloride  of  reddish  colour  gives,  when  dissolved 
in  water  and  filtered,  a  colourless  filtrate,  the 
coloration  is  due  to  the  presence  of  a  specific 
micro-organism  (Oidium  aurantiacum).  In  that 
10 


TESTS    OF   PURITY. 

case  it  is  a  simple  matter  to  destroy  the  mould- 
fungus  by  drying  the  salt. 

2.  When  calcined  in   a  platinum  vessel  ammo- 
nium   chloride    should    leave    no    residue    (fixed 
mineral  matter). 

3.  Its    aqueous    solution    (i  :  10)    should    not 
become  turbid  on  the  addition  of  barium  chloride 
(sulphates),  nor  give  a  precipitate  with  hydrogen 
sulphide  after  neutralisation  with  ammonia  (heavy 
metals). 

4.  The  solution,  after  acidification  with  a  few 
drops    of    hydrochloric    acid,    should    not    give 
a    blue    coloration    with   potassium   ferrocyanide 
(iron). 

5.  On  evaporating  i  grm.  of  the  salt  with  nitric 
acid  (sp.  gr.  1-153)  to  dryness  on  the  water-bath, 
the  residue  should  be  white,  not  yellow  or  brown 
(tarry  substances,  aniline). 


AMMONIUM   MOLYBDATE. 

(NH4)6Mo7O24  +  4H2O  -  1234-6. 

1.  On  dissolving  i  grm.  of  the  salt  in  2-5  c.c.  of 
water,  and  adding  1-5  c.c.  of  ammonia  solution 
(sp.  gr.  0-910)  a  clear  solution  should  be  obtained, 
and  on  then  adding  15  grms.  of  nitric  acid  (sp.  gr. 
i -20)  and  allowing  the  mixture  to  stand  for  two 
hours  while  gently  warmed  it  should  not  give  a 
yellow  sediment  (phosphoric  acid). 

2.  An  ammoniacal  solution  of  the  salt  should 
not  alter  on  the  addition  of  ammonium  sulphide 
(heavy  metals). 

3.  A   solution   to   which   nitric   acid   has   been 
added    should    not    alter    on    the    addition    of 
barium  chloride  (sulphates),  or  of   silver  nitrate 
(chlorides) . 

CALIFORNIA   COLLEGt 

«*    PHARMACY 


REAGENTS    AND   REACTIONS. 

AMMONIUM  OXALATE. 
(NH4)aCaO4.HaO;=  142. 

1.  When  the  salt  is  calcined  in  a  platinum  vessel 
it  should  not  leave  any  residue  (non-volatile  sub- 
stances, alkali  salts). 

2.  The  aqueous  solution  should  not  alter  when 
treated  with  hydrogen  sulphide  or  with  ammonium 
sulphide    (heavy  metals),  nor  should  it   become 
turbid     on     the     addition    of    barium     chloride 
(sulphates)  or  silver  nitrate  (chlorides). 

3.  Quantitative    Estimation. — This    is    effected 
gravimetrically  by  precipitating  the  oxalic  acid 
with  calcium  chloride,  igniting  the  precipitate  of 
calcium    oxalate,     and    weighing    the    resulting 
calcium  oxide. 

AMYL  ALCOHOL. 
C6HUOH  -  88. 

1.  Pure  amyl  alcohol  has  the  following  physical 
constants  :— Specific    gravity    at    15°    C.,    0*815  > 
boiling  point,  129°  to  131°  C. 

2.  When  evaporated  it  should  not  leave  any 
residue  (absence  of  non-volatile  substances). 

3.  When    shaken    with    an    equal    volume    of 
sulphuric  acid  it  should  give  only  a  yellow  or,  at 
most,  a  reddish  coloration,  not  a  blackish-brown 
one  (absence  of  furfural). 

4.  On  shaking  amyl  alcohol  with  water  acidified 
with  hydrochloric  acid,  separating  the  acid  layer 
and  evaporating  it  on  the  water-bath,  and  taking 
up  the  residue  with  a  little  water,  the  liquid  ought 
not  to  give  a  precipitate  with  the  general  reagents 
for  alkaloids,  and  in  particular  with  the  double 
iodide  of  potassium  and  mercury,  with  a  potassium 

12 


TESTS    OF   PURITY. 

iodide  solution  of  iodine,  etc.  (absence  of  pyridine 
bases). 

ANILINE. 
C6H5NH2  =  93. 

1.  Pure  aniline  has  a  specific  gravity  of  1-026 
at  15°  C.,  and  boils  at  182°  C. 

2.  It   should   dissolve   in  twice   its   volume   of 
hydrochloric  acid  to  form  a  solution  which  should 
remain  clear  even  when  diluted  with  an  equal 
quantity  of  water  and  when  chilled  (absence  of 
hydrocarbons  and  of  nitrobenzene). 

3.  Its   reaction   should   be   absolutely   neutral, 
and  it  should  leave  no  residue  on  evaporation. 


BARIUM  CHLORIDE. 
BaCl2  +  2H2O  =  244. 

1.  Its  solution  should  be  neutral,  and  not  alter 
when    treated    with    hydrogen    sulphide    (heavy 
metals) . 

2.  On  heating  2  grms.  of  the  powdered  salt  with 
10  c.c.  of  strong  hydrochloric  acid  in  a  test-tube 
it  should  not  give  a  yellow  coloration  or  emit 
an  odour  of  chlorine  (chlorates). 

3.  After  separation  of  the  barium  by  means  of 
sulphuric    acid,    the    filtrate,    when    evaporated, 
should  not  leave  any  appreciable  residue  (alkalies, 
lime) . 

4.  On  shaking  the  powdered  salt  with  alcohol  and 
filtering  the  liquid,  the  filtrate  ought  not  to  give 
a  red  tint   to  a  flame,  nor  on  evaporation  leave 
a   deliquescent   residue    (chloride    of    calcium   or 
strontium). 

5.  Quantitative    Estimation. — It    is    estimated 

13 


REAGENTS    AND  REACTIONS. 

gravimetrically   by   precipitating   the   barium    as 
barium  sulphate 

BENZENE. 
C6H6  b*  78. 

1.  Benzene  should  have  a  neutral  reaction  and 
volatilise   completely   when   heated   on   platinum 
foil. 

2.  The  pure   compound  boils   at   80-5  C.,  and 
solidifies  at  o°  C. 

3.  On  shaking  benzene  with  a  few  c.c.   of  a 
solution  of  a  trace  of  isatin  in  about  thirty  times 
its    volume    of    strong    sulphuric    acid,    no    blue 
coloration     should     be     produced    (presence     of 
thiophen) . 

4.  When    treated    with    strong    sulphuric    and 
nitric  acids  it  should  emit  the  characteristic  odour 
of  bitter  almonds.     This  reaction  is  particular!}7 
useful  for  the  identification  of  benzene  and  for 
differentiating  it  from  petroleum  spirit. 


BISMUTH   NITRATE. 
Bi(N03)3  +  5H20  =  481-11. 

1.  On    dissolving    neutral     (normal)     bismuth 
nitrate  in  dilute  nitric  acid,  and  treating  part  of  the 
solution  with  silver  nitrate  no  turbidity  should 
result   (bismuth  chloride),  whilst  the  other  part 
should  not  give  a  precipitate  when  treated  with 
barium  chloride  (sulphates). 

2.  The  nitric  acid  solution  should  not  give  a  blue 
coloration    with    potassium    ferrocyanide    (ferric 
salts). 

3.  It  should  not  become  turbid  on  the  addition 
of  sulphuric  acid  (lead),  nor  when  treated  with 

14 


TESTS    OF  PUR 

ammonia  in  excess  and  filtered  soid  it^yield  a 
blue  coloration  (copper). 

4.  When  a  small  quantity  of  the  salt  is  mixed 
with  water  and  boiled  with  sulphuric  acid  until  all 
nitric  acid  has  been  eliminated,  and  the  liquid 
diluted  with  water  and  tested  in  Marsh's  apparatus, 
it  should  not  produce  spots  or  black  rings  (arsenic). 

5.  Quantitative    Estimation. — The    bismuth    is 
estimated  gravimetrically  in  the  form  of  bismuth 
oxide. 

BROMINE  WATER. 

1.  On  evaporating  10  to   20    c.c.    of  bromine 
water  it    should    not    leave    any    residue    (non- 
volatile mineral  matter). 

2.  Twenty  c.c.  of  the  bromine  water  are  acidified 
with  nitric  acid  and  treated  with  silver  nitrate, 
the  resulting  precipitate  washed  and  digested  with 
five  to  six  times  its  volume  of  15  per  cent,  ammo- 
nium carbonate  solution,  and  the  liquid  filtered. 
The  filtrate  should  not  give  a  precipitate  when 
treated  with  potassium  bromide  solution  (absence 
of  chlorine). 

3.  From  20  to  40  c.c.  of  the  bromine  water  are 
heated  with  iron  powder,  and  the  mixture  shaken 
until  decolorised  and  then  filtered.     The  filtrate, 
which  will  contain  ferrous  bromide  (and  iodide  if 
present),   is  treated  with  a  few  drops  of  ferric 
chloride  solution,  which  will  not  act  on  the  bromide, 
but  will  decompose  any  ferrous  iodide,  liberating 
the  iodine,  which  can  be  identified  by  means  of 
starch  paste  (blue  coloration)  or  carbon  bisulphide 
(violet  coloration)  (presence  of  iodine) . 

4.  On  treating  bromine  water  with  potassium 
hydroxide   or   sodium    hydroxide   a   clear   liquid 
should  be  obtained,  and  no  heavy  insoluble  drops 
should  be  formed  (presence  of  organic  bromine 
compounds). 

5.  Quantitative  Estimation  (see  Chlorine  Water). 

15 


REAGENTS    AND   REACTIONS. 

CALCIUM  CHLORIDE. 

CaCl2  +  6H2O  =  219. 

1.  When  dissolved  in  10  per  cent,  of  its  quantity 
of  water  it  should  yield  a  clear,  neutral  solution. 

2.  On  treating  the  solution  with  ammonia  it 
should  not  give  a  white  precipitate,  which  would 
indicate  aluminium,  or  a  reddish  precipitate  of 
ferric  salts. 

3.  The  solution  when  rendered  slightly  acid  with 
hydrochloric  acid  and  treated  with  barium  chloride 
ought  not  to  become  turbid  (sulphates) ,  and  should 
not   give   a  precipitate   with   hydrogen   sulphide 
(heavy  metals) ,  or  a  blue  coloration  with  potassium 
ferrocyanide  (ferric  salts). 

4.  On  heating  2  grms.  of  the  salt  with  sodium 
hydroxide  solution  no  odour  of  ammonia  should  be 
developed  (ammonium  salts). 

5.  Quantitative    Estimation. — The    calcium    is 
precipitated  as  calcium  oxalate,  and  the  precipitate 
ignited  and  weighed  as  calcium  oxide.    The  chlorine 
is  estimated  gravimetrically  as  silver  chloride. 

CARBON  BISULPHIDE. 

CS2  =  76-14. 

1.  Pure    carbon   bisulphide   has   the   following 
physical  constants  : — Specific  gravity  at  20°  C.  = 
1-262  ;  boiling  point,  46°  C. 

2.  It  should  have  a  neutral  reaction  (absence  of 
acid  products)    and  should  volatilise  completely 
when  heated  (absence  of  non-volatile  substances). 

3.  It  should  not  darken  on  treatment  with  lead 
acetate  (hydrogen  sulphide). 

4.  Water  with  which  it  has  been  shaken  ought 
not   to    give    a    turbidity   with    barium    chloride 

16 


TESTS   OF   PURITY. 

(sulphates),  or  decolorise  potassium  permanganate 
(sulphur  dioxide). 

5.  When  evaporated  it  should  not  leave  a 
residue  which  when  heated  with  potassium 
hydroxide  forms  a  substance  which,  on  acidification 
with  hydrochloric  acid,  emits  an  odour  of  hydrogen 
sulphide  (sulphur). 

CHLORINE  WATER. 

1.  Chlorine  water  should  be  completely  volatile. 
On  evaporating  10  c.c.  in  a  basin  no  trace  of 
residue  should  be  left  (non- volatile  mineral  matter) . 

2.  Thirty  c.c.  are  shaken  with  5  to  8  grms.  of 
metallic  mercury  until  the  odour  of  chlorine  has 
completely  disappeared,  when  the  liquid  is  filtered. 
The  filtrate  should  not  give  a  white  precipitate 
with  silver  nitrate,  nor  turn  red  litmus  paper  blue 
(absence  of  hydrochloric  acid) . 

3.  Quantitative    Estimation. — This    is    effected 
volumetrically  by  two  methods  :  (i)  Ten  c.c.  of  the 
chlorine   water   are   treated   with   an    excess    of 
potassium  iodide  solution  (i  :  20),  and  the  liberated 
iodine   titrated   with   N/io   sodium   thiosulphate 
solution,  with  starch  paste  as  indicator  (i  c.c.  of 
thiosulphate  solution  =  0-00355  grm.  of  chlorine) 
(Wagner's  method).     (2)  The  chlorine  in  chlorine 
water  is  titrated  with  N/io  arsenious  anhydride 
solution,  with  starch  iodide  as  indicator. 


CHLOROFORM. 
CHCLj  =  119-1, 

1.  Pure  chloroform   has   a  specific  gravity  of 
1*502  at  150'  C.,  and  boils  at  62-05°  C. 

2.  Its  reaction  should  be  neutral  (absence  of 
hydrochloric  acid  or  acid  products),  and  it  should 

R.R.  17  2 


REAGENTS   AND   REACTIONS. 

volatilise  completely  when  heated  in  a  platinum 
basin  (non-volatile  mineral  matter). 

3.  Water  with  which  it  has  been  shaken  ought 
not  to  have  an  acid  reaction,  nor  to  give  a  white 
precipitate    (hydrochloric    acid)    or   a   yellow    or 
reddish  precipitate  (arsenious  or  arsenic  acid)  with 
silver  nitrate. 

4.  When  5  c.c.  of  the  chloroform  are  shaken  with 
5  c.c.  of  a  solution  of  zinc  iodide  or  of  cadmium 
iodide  mixed  with  starch  the  reagent  should  not  be 
coloured  blue,  nor  should  the  chloroform  become 
red  (chlorine). 

5.  On  shaking  20  c.c    with   15   c.c.  of  strong 
sulphuric  acid  in  a  tube  previously  rinsed  with 
the  same  acid,  a  yellowish-brown  coloration  should 
not    appear    after    twenty-four    hours    (ethylene 
chloride,  chlorides  of  amyl  compounds). 

6.  When  allowed  to  evaporate  spontaneously  on 
paper  it  ought   not    to    leave    a    spot  with    an 
unpleasant  odour  (fusel  oil,  phosgene,  etc.). 

7.  It  should  not  reduce  silver  nitrate  either  in 
the  cold  or  on  heating,  nor  give  a  yellow  or  brown 
coloration    when    treated    with    a    fragment    of 
potassium  hydroxide  (aldehydes). 

8.  When  shaken  with  a  very  dilute  solution  of 
potassium  bichromate  acidified  with  sulphuric  acid 
it  should  not  produce  a  green  coloration,  and  it 
ought  to  remain  clear  and  colourless  on  contact 
with  magenta  (absence  of  alcohol) . 

9.  On  shaking  20  c.c.  of  chloroform  with  15  c.c. 
of  strong  sulphuric  acid  to  which  has  been  added 
4  drops  of  formaldehyde,   no   coloration  should 
appear  after  half  an  hour  (absence  of  amyl  alcohol, 
tertiary  butyl  alcohol,  benzene,  thiophen,   amyl 
chloride). 

10.  When  shaken  with  the  iodide  of  ammonium 
and  mercury  it  ought  not  to  give  a  red  coloration, 
due  to  the  formation  of  red  mercuric  iodide  (water). 

IT.  Quantitative  Estimation. — The  chloroform 
18 


TESTS   OF   PURITY. 

is  decomposed  with  an  excess  of  alcoholic  potassium 
hydroxide  solution,  and  the  resulting  liquid  is 
acidified  with  nitric  acid  and  treated  with  silver 
nitrate.  The  amount  of  chloroform  is  calculated 
from  the  weight  of  silver  chloride  produced. 

CHROMIC  ACID. 
CrOH  =  100  (Chromic  Anhydride). 

1.  On  treating  2  grms.  of  chromic  anhydride  with 
20  c.c.  of  water  a  clear  solution  should  be  obtained, 
which  does  not  become  turbid  or  yield  a  precipitate 
when  treated  with  a  few  drops  of  hydrochloric  acid 
and  with  barium  chloride   (absence  of  sulphuric 
acid). 

2.  When  o-i  grm.  is  heated  carefully  in  a  porce- 
lain basin  oxygen  is  liberated  and  a  green  residue 
of  chromic  oxide  is  left.     The  latter  when  treated 
with   water   ought    to    be    quite   insoluble  ;     the 
aqueous  extract  should  be  quite  colourless  ;    and 
when   filtered   and   evaporated   should   leave   no 
residue  (absence  of  potassium  chromate). 

COBALT  NITRATE. 
Co(NO3)2  +  6H2O  =  290-1. 

1.  A  solution  of  cobalt  nitrate  (i  :  20)  ought  not 
to  become  turbid  on  the  addition  of  barium  chloride 
(sulphates). 

2.  On  dissolving  2  grms.  in  50  c.c.   of  water, 
adding  2  c.c.  of  hydrochloric  acid,  and  treating  the 
solution   with   hydrogen   sulphide,    no    alteration 
should  take  place. 

3.  When  2  grms.   are  dissolved  in  water  and 
treated  with  ammonia  and  ammonium  sulphide  in 
excess,  the  filtrate  should  leave  no  residue  when 
evaporated  on  the  water  bath  (alkaline  salts)  . 


PHARMACY 


REAGENTS  AND   REACTIONS. 

COPPER  SULPHATE. 
CuSO4  +  5H2O  =  24972. 

1.  One  grm.  of  the  salt  is  dissolved  in  50  c.c.  of 
water,  and  the  solution  acidified  with  hydrochloric 
acid  and  treated  with  hydrogen  sulphide   until 
precipitation    of    the    copper    is    complete.     The 
filtrate  when  evaporated  to  dryness  on  the  water- 
bath  ought  not  to  leave  any  residue  (heavy  metals, 
alkali  salts). 

2.  The  aqueous  solution,  treated  with  ammonia 
in  excess,  ought  to  give  a  clear  blue  liquid,  and  no 
reddish  precipitate  should  separate  (iron  salts). 

3.  Quantitative    Estimation. — The    copper    is 
estimated  gravimetrically  as  oxide  or  as  sulphide, 
and  also  electrolytically  as  metallic  copper. 

ETHER. 

(C2H5)20  =  74-08. 

1.  Pure  ether  has  a  specific  gravity  of  0-720  at 
15°  C.  and  boils  at  34*6°  C.     When  evaporated  it 
should    leave    no    residue    (non-volatile    mineral 
matter),    and    should    have    a    neutral    reaction 
(absence  of  free  acids) . 

2.  If,  on  evaporation,  some  small  drops  are  left 
(water),  these  should  not  have  an  acid  reaction,  and 
when  treated  with  barium  chloride  should  not  give 
a  white  precipitate  (sulphuric  acid). 

3.  It    should    dissolve    completely    in    strong 
sulphuric  acid  (absence  of  petroleum  spirit). 

4.  When  evaporated  it  should  not  leave  a  residue 
of  oily  drops,  which  have  an  unpleasant  odour  and 
become  black  on  treatment  with  strong  sulphuric 
acid  (amyl  alcohol). 

5.  On  shaking  ether  with  a  few  drops  of  potassium 

20 


TESTS   OF  PURITY. 

bichromate  solution  and  a  few  drops  of  dilute 
sulphuric  acid,  it  should  not  separate  from  the 
mixture  as  a  blue  layer  (hydrogen  peroxide),  nor 
when  shaken  with  potassium  iodide  solution  should 
it  give  a  yellow  coloration  (ozone,  hydrogen 
peroxide) . 

6.  When  shaken  with  solid  potassium  hydroxide 
it  should  not  give  a  yellow  coloration  within  an 
hour  (vinyl  alcohol,  ethyl  aldehyde). 

7.  Anhydrous     copper     sulphate     should     not 
become  blue  on  contact  with  ether,  nor  should  blue 
cobalt  chloride  paper  change  to  red,  nor  should  a 
mixture  in  equal  volumes  of  ether  and  carbon 
bisulphide  yield  a  turbid  liquid  (absence  of  water). 

8.  On  shaking  ether  with  water,  separating  the 
aqueous    layer,    and    heating    it    at    50°  C.    with 
potassium  hydroxide  and  iodine  it  ought  not  to 
form  a  yellow  precipitate  due  to  iodoform  (absence 
of  alcohol)  ;  whilst  on  shaking  10  c.c.  of  ether  with 
10  c.c.  of  water  in  a  graduated  glass  cylinder  the 
aqueous  layer  should  not  increase  by  more  than  a 
tenth  of  its  volume  (alcohol). 

9.  When  ether  is  shaken  with  mercury  (puriss.) 
the  surface  of  the  metal  should  not  become  tar- 
nished   (absence   of   sulphur   and   compounds   of 
sulphur) . 

10.  For   the   detection   of   ethyl   peroxide   see 
for  is  sen's  reaction. 


ETHYL  ACETATE. 
CH3COOC2H5  =  88. 


I. 


The  pure  compound  has  a  specific  gravity  of 
0-899  at  I5°  C-  and  boils  at  72-8°  C. 

2.  It  should  have  a  pleasant  aroma,  be  neutral 
in  reaction,  and  should  volatilise  completely  (acid 
substances,  non-volatile  mineral  matter)/ 
21 


REAGENTS  AND   REACTIONS. 

3.  On  mixing  10  c.c.  of  ethyl  acetate  with  10  c.c. 
of  water  in  a  graduated  cylinder  the  volume  of 
the    aqueous    layer    should    not    exceed    n    c.c, 
(alcohol) . 

4.  On  pouring  i  c.c.  of  ethyl  acetate  on  to  the 
surface    of    i   c.c.    of    strong   sulphuric   acid   no 
coloration  should  be  formed  at  the  zone  of  contact 
(organic  secondary  products,  amyl  derivatives). 

5.  When  shaken  with  anhydrous  copper  sulphate 
it  should  not  cause  the  salt  to  turn  blue  (water). 

6.  When  distilled  at  a  low  temperature  on  the 
water-bath  it  should  not  leave  a  residue  with  a 
pear-like  odour  (amyl  acetate). 

7.  On  shaking  a  small  quantity  of  ethyl  acetate 
with   a  little  water  having  in   suspension   mag- 
nesium  oxide,   and  separating  and  filtering  the 
aqueous  layer,  the  filtrate  should  not  give  a  red 
coloration   with    ferric    chloride   (acetic    acid)    or 
turbidity  with  barium  chloride  (sulphuric  acid). 


FERROUS   SULPHATE. 

FeSO4  +  7H20  -  278-03. 

1.  A  solution  of  ferrous  sulphate  should  have  a 
slight  but  not  pronounced  acid  reaction,  and  on 
triturating  the  salt  with  anhydrous  alcohol  and 
evaporating  the  alcoholic  solution  it  should  not 
leave  a  residue  which  gives  a  red  coloration  with 
salicin    and    effervesces    with    sodium    carbonate 
(absence  of  free  sulphuric  acid). 

2.  The    aqueous    solution    should    not    give    a 
blood-red  coloration  when  treated  with  potassium 
thiocyanate  (ferric  salts). 

3.  The  solution  should  not  darken  on  treatment 
with  hydrogen  sulphide  (heavy  metals),  and  when 
treated  with  ammonia  in  excess  it  should  not  give  a 
blue  filtrate,  but  should  remain  colourless  (copper). 

22 


TESTS   OF  PURITY. 

4.  When     tested     in    Marsh's    apparatus    the 
solution   should   not   yield   black   rings   or   spots 
(arsenic). 

5.  On   heating   a   crystal   of    ferrous   sulphate 
with  a  concentrated  solution  of  potassium  hydroxide 
no    odour    of    ammonia    should    be    perceptible 
(presence  of  ferrous  ammonium  sulphate). 

6.  Quantitative    Estimation. — The    solution    of 
ferrous  sulphate  is  titrated  with  N/io  potassium 
permanganate  solution,  or  with  N/io  potassium 
bichromate  solution,  potassium  ferricyanide  being 
used  as  indicator. 


FERRIC  CHLORIDE. 

Fe2Cl6  +  H20  =  541. 

1.  When  a  rod  is  dipped  into  a  solution  of  ferric 
chloride  and  then  brought  close  to  a  rod  which 
has  been  dipped  in  ammonia  solution,  there  should 
be  no  appearance  of  white  fumes  between  the  rods 
(free  hydrochloric  acid). 

2.  Starch-iodide   paper   should   not    turn   blue 
when  brought  close  to  a  vessel  containing  ferric 
chloride  solution  (free  chlorine). 

3.  When  the  solution,  after  dilution  with  twenty 
times  its  volume  of  water,  is  acidified  with  hydro- 
chloric acid  and  then  tested  with  potassium  ferri- 
cyanide,   it    should   not    give    a   blue    coloration 
(ferrous  salts). 

4.  The  solution  is  diluted  with  water  and  treated 
with  ammonia  in  excess.    The  filtrate  should  not 
give  a  blue  coloration  (copper),  but  should  remain 
colourless.      On    evaporating    a    portion    of    the 
filtrate   it   should   not    leave   any   residue    (fixed 
substances),  whilst  a  second  portion  when  treated 
with  hydrogen  sulphide  should  not  yield  a  white 
precipitate  (zinc) ,  or  a  coloured  precipitate  (copper, 

23 


REAGENTS  AND   REACTIONS. 

lead,  arsenic).  A  third  portion  of  the  filtrate, 
acidified  with  hydrochloric  acid,  should  not  give  a 
turbidity  with  barium  chloride  (sulphates) .  Lastly, 
on  heating  a  portion  of  the  filtrate  to  remove 
ammonia,  cooling  it,  adding  strong  sulphuric  acid, 
and  introducing  ferrous  sulphate  solution  in  such 
a  way  as  not  to  mix  the  two  liquids,  a  brown  ring 
should  not  be  formed  at  the  zone  of  contact  (nitric 
acid). 

5.  The  solution  should  not  yield  a  black  ring 
or  spot  when  tested  in  Marsh's  apparatus  (arsenic). 

6.  It    should    not    decolorise    potassium    per- 
manganate solution  (nitrous  acid). 

7.  It  should  not  become  turbid  on  boiling,  or 
on  the  addition  of  four  times  its  volume  of  con- 
centrated alcohol  (ferric  oxychloride) . 

8.  Quantitative    Estimation. — This    is    effected 
gravimetrically    by    precipitating    the    iron    with 
ammonia,  and  igniting  and  weighing  the  precipi- 
tated ferric  oxide.    Or  for  a  volumetric  estimation 
the  solution  of  ferric  chloride  may  be  treated  with 
an    excess   of   a   standard   solution    of   stannous 
chloride,  and  the  excess  titrated  with  N/io  iodine 
solution.    Ferric  chloride  may  also  be  titrated  with 
titanium  trichloride,  potassium  thiocyanate  being 
used  as  indicator. 

GLYCEROL   (GLYCERIN). 
C8H8O8  =  92-06. 

i.  The  solution  obtained  by  dissolving  10  c.c. 
in  50  c.c.  of  water  should  be  neutral,  and  should 
not  give  a  brown  coloration  with  hydrogen 
sulphide,  or  with  ammonium  sulphide,  nor  should 
it  become  turbid  on  the  addition  of  barium 
chloride  (sulphates),  ammonium  oxalate  (calcium 
salts),  calcium  chloride  (oxalic  acid),  or  silver 
nitrate  (chlorides). 

24 


TESTS   OF  PURITY. 

2.  On  treating  i  c.c.  of  glycerol  with  5  c.c.  of 
Bettendorf  s  reagent  no  coloration  should  appear 
within  an  hour  (arsenic). 

3.  When    heated    on    platinum    foil    it   should 
volatilise  without  leaving  a  residue  (fixed  mineral 
substances),  and  it  should  have  a  neutral  reaction 
(absence  of   acids  and  bases),  and  be  completely 
soluble  in  water  and  in  alcohol  (absence  of  gum 
and  dextrin). 

4.  It  should  not  emit  an  odour  of  rancid  butter, 
even "  when    heated    with    dilute    sulphuric    acid 
(absence  of  butyric  acid). 

5.  When    treated    with    an    equal    volume    of 
ammoniacal  silver  nitrate  solution  it  should  not 
give  a  brown  coloration  (acrolein,  formic  acid). 

6.  It    should    not    reduce    Fehling's    solution 
(dextrose),    even    after    prolonged    boiling    with 
hydrochloric  acid  (sucrose). 

7.  It    should    not    give    a    precipitate    on    the 
addition   of   ammonia,   ammonium  chloride,   and 
sodium  phosphate  (magnesium  chloride). 

8.  The  physical  constants  should  be  determined, 
and  especially  the  specific  gravity,  which  should  be 
1-269  at  T5°c- 


HYDROCHLORIC  ACID. 
HC1  =  36-5. 

1.  On    evaporating    10    grms.    in    a    basin    no 
appreciable    residue    should    be    left    (fixed   sub- 
stances). 

2.  The  acid  diluted  with  10  volumes  of  water 
ought    not    to    turn    starch-iodide    paper    blue 
(chlorine),  nor  change  under  the  action  of  hydrogen 
sulphide  (heavy  metals) . 

3.  The  solution  diluted  as  above  and  treated 
with  barium  nitrate,  either  with  or  without  the 

25 


CQLLtGfc 


REAGENTS  AND   REACTIONS. 

subsequent  addition  of  iodine  until  the  liquid  has 
a  slight  yellow  colour,  ought  not  to  become  turbid, 
or  give  a  precipitate  (sulphuric  and  sulphurous  acid) . 

4.  When  treated  with  potassium  ferrocyanide  it 
ought  not  to  give  a  blue  coloration  or  precipitate 
(ferric  salts). 

5.  When  100  c.c.  of  the  acid  suitably  diluted  are 
treated  with  arsenic-free  zinc  in  Marsh's  apparatus 
no  reaction  should  be  obtained  even  after  twelve 
hours  (absence  of  arsenic) . 

6.  Quantitative    Estimation. — This    is    effected 
gravimetrically  in  the  form  of  silver  chloride,  or 
volumetrically  by  means  of  N-potassium  hydroxide 
solution,  with  phenolphthalein  as  indicator. 


IODINE. 

I  =  127. 

1.  Iodine    should    volatilise    completely    when 
heated  on  platinum  foil  (absence  of  fixed  mineral 
substances  :   graphite,  carbon,  etc.). 

2.  Twenty-five  grms.  of  iodine  are  shaken  with 
100  c.c.  of  water,  the  liquid  filtered,  and  the  yellow 
filtrate   divided  into  two  portions  :     (a)  To   one 
portion  is  added  dilute  sodium  thiosulphate  solu- 
tion until  the  colour  is  removed,  when  a  crystal  of 
ferrous  sulphate  is  introduced,  followed  by  a  few 
drops  of  solutions  of  ferric  chloride  and  of  sodium 
hydroxide,  and  the  mixture  is  heated  for  a  few 
minutes  at  40°  to  50°  C.     When  cold,  the  liquid  is 
acidified  with  dilute  hydrochloric  acid.     It  should 
not  give  a  blue  coloration  or  precipitate  (cyanogen 
iodide),     (b)  The   other  portion,   not   decolorised 
with    thiosulphate,    is    treated    with    i    drop    of 
ammonia  solution,  and  an  excess  of  silver  nitrate 
solution,    and    then    shaken    and    filtered.     The 
filtrate  when  acidified  with  nitric  acid  ought  not  to 

26 


TESTS         ^LJ  ^ 

become  turbid,  or  give  a  white  precipitateYfiodine 
chloride) . 

3.  Quantitative  Estimation. — A  solution  is  pre- 
pared by  shaking  o-i  grm.  of  the  iodine  with 
25  c.c.  of  an  aqueous  solution  of  i  grm.  of  potassium 
iodide,  and  the  iodine  is  titrated  with  N/io  sodium 
thiosulphate  solution,  starch  paste  being  used  as 
indicator.  Under  these  conditions  iodine,  corre- 
sponding to  99-04  per  cent,  of  pure  iodine,  requires 
7-8  c.c.  of  N/io  thiosulphate  solution. 

LEAD  ACETATE. 

Pb(C2H302)2  +  3H20  =  378-99. 

i.  Five  grms.  of  the  salt  are  dissolved  in  100  c.c. 
of  water,  treated  with  a  slight  excess  of  dilute 
sulphuric  acid,  and  filtered.  On  treating  the  fil- 
trate with  ammonia  in  excess  it  ought  not  to  give  a 
blue  coloration  (copper) ,  nor  after  evaporation  and 
ignition  should  it  leave  an  appreciable  residue 
(foreign  metals  in  general). 

MAGNESIUM   SULPHATE. 
MgSO4  +  7H2O  =  246-50. 

1.  A  solution  of  the  salt  slightly  acidified  ought 
not  to  give  a  turbidity  with  hydrogen  sulphide 
(lead,  copper),  nor  turn  blue  on  the  addition  of 
potassium  ferrocyanide  (iron). 

2.  When  acidified  with  nitric  acid  it  ought  not  to 
give  a  precipitate  with  barium  chloride  (sulphates) 
or    with    silver    nitrate    (chlorides)  ;     nor    when 
rendered  alkaline  with  ammonia  and  treated  with 
ammonium    chloride    in    excess    and    ammonium 
oxalate  should  it  give  a  white  precipitate  (calcium 
salts). 

27 


REAGENTS  AND   REACTIONS. 

3.  On  igniting  a  mixture  of  the  salt  with  an  equal 
weight  of  charcoal  and  taking  up  the  residue  with 
water  the  filtrate  should  not  give  a  violet  coloration 
with  sodium  nitroprusside  (alkali  sulphates). 

4.  On  treating  the  solution  with  an  excess  of  a 
concentrated    solution    of    potassium    hydroxide, 
filtering    the    liquid,    and    adding    an    excess    of 
ammonium  chloride  to  the  nitrate  it  ought  not  to 
yield  a  white  gelatinous  precipitate  (aluminium). 

5.  When  i  grm.  of  the  salt  is  powdered  and  mixed 
with  5  c.c.  of  Bettendorf's  reagent  it  should  not 
give  a  brown  coloration  (arsenic). 

6.  Quantitative  Estimation. — The  magnesium  is 
estimated    gravimetrically    as    magnesium    pyro- 
phosphate,   and    the    sulphuric    acid    as    barium 
sulphate. 

MERCURIC  CHLORIDE. 

HgCl2  =  270-9. 

1.  Mercuric     chloride     should     be     completely 
soluble   in   alcohol,    and   not   leave   an   insoluble 
residue   which   turns   black   on   the   addition   of 
potassium  hydroxide  solution,  and  then  yields  a 
filtrate  which,  after  acidification  with  nitric  acid, 
gives  a  turbidity  with  silver  nitrate  (mercurous 
chloride) . 

2.  A  solution  of  mercuric  chloride  should  not 
emit  an  odour  of  ammonia  when  boiled  with  potas- 
sium hydroxide  (ammonium  chloride) . 

3.  The  solution  when  treated  with  excess  of 
hydrogen  sulphide  yields  a  precipitate,  which  when 
washed  and  treated  with  dilute  ammonia  solution 
should  give  a  filtrate  which  on  acidification  with 
hydrochloric    acid   ought    not    to   give    a   yellow 
coloration  (arsenic).     The  filtrate  from  the  hydro- 
gen   sulphide    treatment    should    not    leave    any 
residue    on    evaporation    (absence    of    alkali   and 
alkaline  earth  metals) . 

28 


TESTS   OF  PURITY. 

4.  On  treating  the  salt  with  ether  it  should  not 
leave  an  insoluble  residue  which  reduces  Fehling's 
solution  (sugar). 

5.  Quantitative    Estimation. — This    may    be 
effected  gravimetrically  as  sulphide  or  as  mercurous 
chloride,  and  electrolytically  as  metallic  mercury. 
For  a  volumetric  estimation  an  alkaline  solution  of 
the  salt  is  treated  with  an  excess  of  a  standard 
solution  of  a  ferrous  salt,  and  the  excess  titrated 
with  N/io  potassium  permanganate  solution. 

MERCUROUS   NITRATE. 
Hg2(N03)2  +  2H20  =  560. 

1.  When  heated  in  a  porcelain  basin,  it  should 
leave  no  residue  (fixed  foreign  substances). 

2.  One  grm.  of  the  salt  should  dissolve  in  I  c.c. 
of  water  containing  3  drops  of  25  per  cent,  nitric 
acid,  yielding  a  clear  solution,  without  any  separa- 
tion of  a  yellow  powder  (basic  mercury  nitrate). 

3.  On  mixing  i  grm.  of  the  salt  with  i  grm.  of 
sodium  chloride  and  10  c.c.  of  water,  and  filtering 
the  liquid,  there  should  not  be  a  white,  yellow,  or 
grey  residue  (basic  salt),  and  the  filtrate  should 
not   give    a   precipitate   with   stannous   chloride, 
ammonia,  or  hydrogen  sulphide  (mercuric  nitrate) . 

4.  Quantitative    Estimation. — The    mercury    is 
estimated  gravimetrically  as  mercurous  chloride, 
or  electrolytically  as  metallic  mercury. 

METHYL  ALCOHOL. 
CH8OH  =  31-93. 

1.  Pure  methyl  alcohol  boils  at  65°  to  66°  C., 
and  has  a  specific  gravity  of  07997  at  15°  C. 

2.  It  should  have  a  neutral  reaction  and  be 

29 


REAGENTS  AND   REACTIONS. 

completely  volatile  (absence  of  acid  products  and 
fixed  substances). 

3.  When  treated  with  a  solution  of  magenta 
which  has  been  decolorised  with  sulphur  dioxide 
it  should  not  become  pink  (absence  of  aldehydes). 

4.  When  shaken  with  twice  its  volume  of  strong 
sulphuric  acid  it  should  not  give  a  yellow  or  brown 
coloration  (absence  of  tarry  substances). 

5.  When     shaken    with     alcoholic    potassium 
hydroxide  solution  it  should  not  turn  yellow  or 
brown,  and  should  not  decolorise  a  o-oi  per  cent, 
solution  of  potassium  permanganate  which  has 
been  added  to  it  in  the  proportion  of  a  fifth  of  its 
volume  (absence  of  a  notable  quantity  of  alde- 
hydes) . 

6.  It  should  not  contain  acetone.     The. test  is 
made  by  treating  i  c.c.  of  the  methyl  alcohol  with 
10  c.c.  of  a  dilute  solution  of  potassium  hydroxide, 
and   adding,  little  by  little,  a  potassium  iodide 
solution  of  iodine  ;    in  the  presence  of  acetone  a 
yellow  precipitate  of  iodoform  will  be  obtained. 

7.  Quantitative    Estimation. — The    method    is 
based  on  the  transformation  of  the  methyl  alcohol 
into  dimethyl  iodide.    Fifteen  grms.  of  phosphorus 
di-iodide  are  placed  in  a  flask  which  is  fitted  with  a 
thistle-funnel  with  a  stop-cock,  and  is  connected 
with  a  distillation  apparatus,  and  5  c.c.  of  the 
methyl    alcohol    are    introduced,  drop    by  drop, 
through  the  thistle-funnel,  and  then  5  c.c.  of  a 
solution  of  I  part  of  iodine  in  I  part  of  hydriodic 
acid  (sp.  gr.  1-7).    After  five  minutes  the  flask  is 
heated  on  the  water  bath,  and  the  distillate  is 
collected  in  a  graduated  cylinder  partially  filled 
with  water.     After  the  distillation  the  condenser 
is  washed  with  a  little  water,  and  the  washings 
collected  in  the  cylinder.     The  contents  of  the 
latter  are  diluted  to  a  definite  volume  with  water, 
shaken  and  allowed  to  stand,  and  the  volume  in 
c.c.  of  methyl  iodide  which  separates  is  measured. 

30 


TESTS   OF  PURITY. 

Five  c.c.  of  pure  anhydrous  methyl  alcohol  yield 
7-2  c.c.  of  methyl  iodide. 


NITRIC   ACID. 
HN03  =  63. 

1.  Nitric   acid  should  leave  no   residue   when 
evaporated  in  a  basin  (fixed  mineral  substances). 

2.  When  diluted  with  ten  volumes  of  water  it 
should  not  give  a  turbidity  with  barium  chloride 
(sulphates),  or  with  silver  nitrate  (chlorides),  or  a 
blue  coloration  with  potassium  ferrocyanide  (ferric 
salts). 

3.  When  diluted  with  twice  its  volume  of  water 
and  shaken  with  chloroform  it  should  not  colour 
the  latter  violet,  even  after  the  addition  of  a  frag- 
ment of  metallic  zinc  to  the  acid  layer  (absence  of 
iodine  and  iodic  acid) . 

4.  Quantitative    Estimation. — This    is    effected 
volumetrically    by    titration    with    N-potassium 
hydroxide  solution,  with  phenolphthalein  or  tur- 
meric tincture  as  indicator. 

OXALIC  ACID. 
C2H2O4  +  2H2O  =  125-64. 

1.  Oxalic  acid  should  be  perfectly  white,  and 
soluble  in  water. 

2.  When  heated  it  should  volatilise  completely 
(absence  of  fixed  substances). 

3.  On    treating    its    solution    with    potassium 
acetate  it  ought  not  to  give  a  crystalline  precipitate 
(absence  of  tartaric  acid). 

4.  Its  solution  acidified  with  nitric  acid  ought 
not  to  become  turbid  with  silver  nitrate,  or  with 
barium  chloride  (absence  of  chlorides  and  sulphates). 


REAGENTS  AND   REACTIONS. 

5.  The  solution,  when  acidified  with  sulphuric 
acid  and  treated  with  a  crystal  of  brucine,  should 
not  give  a  red  coloration  (absence  of  nitric  acid). 

6.  When  treated  with  hydrogen  sulphide  the 
solution  should  not  become  turbid  or  give  a  pre- 
cipitate, even  after  neutralisation  with  ammonia 
(absence  of  heavy  metals) . 

7.  On    boiling    the    solution    with    potassium 
hydroxide  it  should  not  emit  alkaline  vapours  with 
an  odour  of  ammonia  (ammoniacal  salts). 

8.  Quantitative  Estimation. — Oxalic  acid  may 
be  estimated  gravimetrically  by  precipitating  it 
as  calcium  oxalate,  igniting  the  precipitate,  and 
weighing     the     resulting     calcium     oxide.      For 
volumetric  estimation  it  may  be  titrated  with  a 
normal  solution  of  potassium  or  sodium  hydroxide, 
with  phenolphthalein   as   indicator,  or  with  N/io 
potassium  permanganate  solution. 

PETROLEUM  SPIRIT   (BENZINE). 

1.  When  evaporated  it  should  not  leave  any 
appreciable  residue. 

2.  When  shaken  with  i  part  of  strong  sulphuric 
acid  and  4  parts  of  nitric  acid  it  should  not,  after 
cooling,  emit  an  odour  of  bitter  almonds  (benzene) , 
nor  give  an  intense  brown  coloration. 

3.  When  i  c.c.  of  petroleum  spirit  is  mixed  with 
5  c.c.  of  an  ammoniacal  solution  of  silver  nitrate 
and  heated  for  a  short  time,  the  mixture  should  not 
become  black  (absence  of  sulphur  compounds), 

PHENOL. 
C6H5OH  =  94-05. 

i.  Phenol  should  be  crystalline  and  colourless, 
and  should  volatilise  completely  when  heated  on 
platinum  foil  (fixed  mineral  substances). 
32 


TESTS   OF  PURITY. 

2.  It  should  melt  at  42°  to  43°  C.  (absence  of 
cresol,  which  melts  at  35°  C.)  and  should  be  soluble 
in  fourteen  to  fifteen  times  its  volume  of  water 
(cresol). 

3.  It  should  not  give  a  black  coloration  with 
sulphuric  acid  (tarry  substances). 

4.  Quantitative     Estimation. — This     may     be 
effected  gravimetrically  by  precipitating  the  phenol 
with  bromine  water,  and  weighing  the  resulting 
tribromphenol.     A  more  accurate  method  is  to 
estimate  the  phenol  volumetrically  by  treating  it 
with  a  measured  excess  of  bromine  (derived  from  a 
standard    solution    of    potassium    bromide    and 
bromate),    then    adding    potassium    iodide,    and 
titrating  the  liberated  iodine  with  N/io  sodium 
thiosulphate  solution,   with  starch  paste   as  in- 
dicator. 

PHOSPHORIC  ACID. 
H3PO4  =  98-02. 

1.  Phosphoric    acid    should    not    decolorise    a 
sulphuric  acid  solution  of  indigo,  nor,  when  its 
solution   is   treated   with   a   solution   of   ferrous 
sulphate  in  such  a  way  that  the  two  liquids  do  not 
mix,  should  a  brown  ring  be  formed  at  the  zone  of 
contact  (nitric  acid). 

2.  The  acid  diluted  with  water  (i  :  3)  should  not 
become  turbid  on  the  addition  of  barium  chloride 
(sulphates) ,  or  silver  nitrate  (chlorides). 

3.  When  treated  with  five  times  its  volume  of 
Bettendorf's  reagent  it  should  not  give  a  brown 
coloration,  even  after  three  or  four  hours  (arsenic). 

4.  It  should  not  yield  a  white  precipitate  on 
treatment   with   mercuric   chloride   solution,   nor 
decolorise  O-T  per  cent,  potassium  permanganate 
solution  (lower  acids  of  phosphorus). 

5.  The  solution  when  acidified  with  hydrochloric 

33  fORNfA   COLLt( 

PHARMACY 


REAGENTS   AND   REACTIONS. 

acid  and  treated  with  hydrogen  sulphide  should  not 
give  a  turbidity  or  precipitate  (heavy  metals). 

6.  The  solution  should  not  become  turbid  on  the 
addition  of  alcohol  and  ammonia  in  slight  excess 
(acid  phosphates  of  calcium  and  magnesium) . 

7.  It  should  not  leave  any  residue  after  long- 
continued  ignition  on  platinum  foil   (fixed  sub- 
stances) . 

8.  When  diluted  with  ten  times  its  volume  of 
water  it  should  not  precipitate  albumin   (meta- 
phosphoric  acid). 

9.  Quantitative  Estimation. — Phosphoric  acid  is 
estimated    gravimetrically    as    magnesium    pyro- 
phosphate,   by    precipitating    it    as    ammonium 
magnesium    phosphate    by    means    of    magnesia 
mixture  and  igniting  the  salt  thus  obtained. 

It  may  also  be  estimated  gravimetrically  as 
ammonium  phosphomolybdate. 

The  volumteric  estimation  of  free  phosphoric 
acid  presents  some  difficulty  owing  to  its  behaving 
in  a  special  way  with  indicators.  It  reacts  with 
phenolphthalein  first  as  regards  two  atoms  of 
hydrogen,  whilst  in  the  case  of  the  third  atom  it  only 
reacts  after  methyl  orange  has  been  added. 

It  may  also  be  estimated  volumetrically  by  using 
a  standard  solution  of  uranyl  acetate,  with 
potassium  ferrocyanide  as  an  outside  indicator. 
In  the  presence  of  excess  of  uranyl  acetate  a  red 
precipitate  is  obtained. 


POTASSIUM  BICHROMATE. 
K2Cr2O7  =  294-20. 

i.  A  solution  of  the  salt,  acidified  with  hydro- 
chloric acid,  should  not  give  a  precipitate  with 
barium  chloride  (absence  of  sulphates) ,  nor,  when 
strongly  acidified  with  nitric  acid,  should  it  give 
34 


TESTS   OF  PURITY. 

a   precipitate   with    silver   nitrate    (exclusion   of 
chlorides). 

2.  On  treating  the  solution  with  ammonia  and 
ammonium  oxalate,  it  should  not  give  a  white 
precipitate  insoluble  in  acetic  acid  (absence  of 
calcium  salts). 

POTASSIUM  BROMIDE. 

KBr  =  119. 

1.  A  solution  of  potassium  bromide  should  not 
turn  yellow  on  treatment  with  dilute  hydrochloric 
acid  (bromates) ,  nor  have  an  alkaline  reaction,  nor 
become  turbid  with  lime-water   (potassium  car- 
bonate). 

2.  The  solution,  when  acidified  with  hydrochloric 
acid,  should  not  give   a  turbidity  with  barium 
chloride  (potassium  sulphate). 

3.  When  treated  with  a  drop  of  potassium  nitrite 
solution  and  with  starch  paste  and  hydrochloric 
acid,  it  should  not  give  a  blue  coloration  (potassium 
iodide). 

4.  On  distilling  5  grms.   of  the  bromide  with 
5  grms.  of  potassium  chromate  and  15  grms.  of  pure 
sulphuric  acid  in  a  small  retort  connected  with  a 
receiver  containing  dilute  ammonia  solution,  the 
distillate  should  not  have  a  yellow  colour  (chlorides) . 

5.  On  boiling  a  mixture  of  i  part  of  bromide 
with  i  part  of  iron  filings,  i  part  of  zinc  dust,  i  part 
of  potassium  hydroxide,  and  5  parts  of  water  there 
should  be  no  evolution  of  ammonia  (nitrates) . 

6.  The  solution  ought  not  to  darken  on  treatment 
with  hydrogen  sulphide  (heavy  metals),  nor  give  a 
blue  coloration  with  potassium  ferrocyanide  (iron 
salts). 

7.  No  precipitate  should  be  obtained  on  mixing 
a  solution  of  the  salt  with  ammonia  and  sodium 
phosphate  (magnesium  bromide). 

35  3-2 


REAGENTS  AND   REACTIONS. 

8.  On  heating  a  crystal  of  the  salt  in  a  Bunsen 
flame,  it  should  not  impart  a  yellow  colour  to  the 
flame  (sodium  salts). 

9.  Quantitative  Estimation. — Three  grms.  of  the 
salt  (previously  dried  at  110°  C.)  are  dissolved  in 
100  c.c.  of  water.     Ten  c.c.  of  the  solution  are 
diluted  with  70  c.c.  of  water,  and  titrated  with 
N/io    silver    nitrate    solution,    with    potassium 
chromate  as  indicator.     Not  more  nor  less  than 
25*4  c.c.  of  the  silver  nitrate  solution  should  be 
required.     A  greater  or  smaller  quantity  indicates 
the  presence  of  chlorides  or  iodides  in  the  salt. 


POTASSIUM   CYANIDE. 
KCN  =  65. 

1.  An  aqueous  solution  of  the  salt  (i  :  20)  should 
not  effervesce  on  the  addition  of  hydrochloric  acid 
(potassium  carbonate). 

2.  The  acidified  solution  should  not  give  a  brown 
or  black  coloration  on  treatment  with  hydrogen 
sulphide  (heavy  metals),  nor  blacken  lead  acetate 
paper  (potassium  sulphide),  nor  give  a  turbidity 
with  barium  chloride  (potassium  sulphate) . 

3.  The   solution   when    slightly   acidified   with 
hydrochloric  acid  should  not  give  a  reddish  colour 
with  ferric  chloride  (potassium  thiocyanate) ,  or  a 
blue  coloration  (potassium  ferrocyanide) . 

4.  Quantitative  Estimation. — Ten  c.c.  of  a  i  per 
cent,  aqueous  solution  of  potassium  cyanide  are 
diluted  with  90  c.c.  of  water,  a  trace  of  sodium 
chloride  solution  added,  and  the  liquid  titrated 
with   N/io   silver   nitrate   solution   until   a   faint 
persistent  turbidity  is  obtained.     Not  less  than 
7-5  c.c.  of  the  silver  nitrate  solution  should  be 
consumed,  since  potassium  cyanide  should  contain 
at  least  97*5  per  cent,  of  KCN. 

36 


TESTS   OF  PURITY. 

POTASSIUM   FERRICYANIDE. 

K3Fe(CN)6  =  229. 

1.  When  crystals  of  potassium  ferricyanide  are 
washed  superficially  with  water,  and  the  solution, 
which  should  be  extremely  dilute,  is  treated  with 
ferric  chloride  solution,  there  should  not  be  any 
blue  coloration  (potassium  f errocyanide) . 

2.  On  acidifying  10  c.c.  of  a  3  per  cent,  solution 
of  the  salt  with  2  drops  of  hydrochloric  acid  and 
adding  barium  chloride  no  turbidity  or  precipitate 
should  be  obtained  (potassium  sulphate). 

3.  A  mixture  of  0*5  grm.  of  ferricyanide  and 
i  grm.  of  potassium  nitrate  absolutely  free  from 
chloride  is  fused  in  a  porcelain  crucible,  the  fused 
mass  taken  up  with  water  and  filtered,  and  the 
filtrate  acidified  with  nitric  acid  and  treated  with 
silver  nitrate.     A  white  precipitate  should  not  be 
obtained  (absence  of  potassium  chloride) . 


POTASSIUM   FERROCYANIDE. 

K4Fe(CN)6  +  H20  -  422. 

1.  When  a  few  crystals  are  dissolved  in  water, 
and   the  solution   treated   with   dilute   sulphuric 
acid,  there  should  be  no  effervescence  (potassium 
bicarbonate) . 

2.  Ten  c.c.  of  a  5  per  cent,  solution  acidified  with 
2  drops  of  hydrochloric  acid  should  not  give  a 
precipitate   on   the   addition   of  barium   chloride 
(potassium  sulphate). 

3.  Detection  of  Chlorides. — The  test  is  applied 
in  the  same  way  as  in  the  case  of  potassium  ferri- 
cyanide (q.v.). 

37 


REAGENTS  AND   REACTIONS. 

POTASSIUM  HYDROXIDE. 
KOH  =  56-16. 

it  Five  grms.  of  the  potassium  hydroxide  are  dis- 
solved in  10  c.c.  of  water  in  a  platinum  basin,  and 
the  solution  acidified  with  acetic  acid,  then  ren- 
dered slightly  alkaline  with  ammonia,  diluted  with 
water  to  100  c.c. ,  boiled  on  the  water-bath  so  long  as 
an  odour  of  ammonia  is  perceptible,  and  then 
allowed  to  stand  for  some  hours.  There  should  be 
no  separation  of  a  white,  gelatinous,  flocculent  pre- 
cipitate (alumina). 

2.  The    aqueous   solution    should    not    become 
turbid  with  ammonium  oxalate  (calcium) ,  or  with 
sodium   phosphate    (magnesium),   nor   show   any 
alteration  on  treatment  with  ammonium  sulphide 
(heavy  metals). 

3.  Five  grms.  are  dissolved  in  a  platinum  basin, 
the  solution  treated  with  hydrochloric  acid  in  excess, 
and  evaporated  on  the  water-bath,  and  the  residue 
heated  for  some  hours  in  an  oven  at  150°  C.     When 
the  residue  is  taken  up  with  water,  it  should  give  a 
clear  solution,  and  there  should  be  no  separation 
of  a  white  deposit  (silica). 

4.  Six  grms.  of  the  sample  are  dissolved  in  200  c.c. 
of  water,  and  the  solution  acidified  with  hydro- 
chloric acid.     Half  of  the  solution  is  treated  with 
barium  chloride  and  the  other  half  with  sulphuric 
acid,  and  both  are  boiled  for  ten  minutes,  and  then 
allowed  to  stand  for  six  hours.     There  should  be  no 
precipitate  or  turbidity  formed,  in  the  first  case 
indicating  sulphates,   and  in   the  second  barium 
salts. 

5.  The  solution,  when  acidified  with  nitric  acid, 
should  give  only  a  faint  opalescence  with  silver 
nitrate  (chlorides). 

6.  Fifty  grms.  of  the  sample  are  dissolved  in 

38 


TESTS  OF  PURITY. 

200  c.c.  of  water,  and  the  solution  treated  with 
5  grms.  of  arsenic-free  iron  which  has  been  reduced 
by  means  of  hydrogen,  or  with  zinc  dust,  and  dis- 
tilled, and  the  distillate  is  collected  in  20  c.c.  of 
water  containing  i  per  cent,  of  sulphuric  acid.  The 
distillate  is  rendered  alkaline  with  potassium 
hydroxide  and  treated  with  Nessler's  reagent.  It 
should  not  give  a  yellow  coloration  or  precipitate 
(absence  of  nitric  and  nitrous  acids). 

7.  On  treating  5  grms.  of  the  sample  with  30 
grms.  of  alcohol  (sp.  gr.  0-83)  it  should  yield  a 
clear   colourless   solution   (absence   of    potassium 
carbonate). 

8.  Quantitative    Estimation. — This   is    effected 
volumetrically      by      titrating      the      potassium 
hydroxide  with   N/io   sulphuric   or   hydrochloric 
acid,  with  phenolphthalein  or  litmus  tincture  as 
indicator. 

POTASSIUM   IODIDE. 

KI  =  166-12. 

1.  On    introducing    a    small    quantity    of    the 
previously  powdered  and  dried  salt  into  a  colourless 
gas   flame,  it   should   give   a   pronounced   violet 
coloration,  without  any  yellow  coloration  (sodium 
salts). 

2.  A  solution  of  0-5  grm.  of  the  iodide  in  10  c.c. 
of  water  is  treated  with  a  drop  of  phenolphthalein 
solution.     If  a  pink  coloration  is  obtained  potas- 
sium carbonate  is  present.     The  latter  may  also  be 
quantitatively  estimated  by  titration  with  N/ioo 
hydrochloric  acid.     One  grm.  of  potassium  iodide 
should   require   not   more   than    1-4   c.c.    of   the 
standard  acid  for  neutralisation. 

3.  The  solution  should  not  yield  a  turbidity  or 
precipitate  with  hydrogen  sulphide  (heavy  metals, 
especially  copper  and  lead). 

39 


REAGENTS  AND   REACTIONS. 

4.  The  solution,  when  acidified  with  hydrochloric 
acid,  ought  not  to  become  turbid  with  barium 
chloride  (sulphates). 

5.  On  treating  10  c.c.  of  a  5  per  cent,  aqueous 
solution  of  the  salt  with  a  crystal  of  ferrous  sulphate, 
adding  a  drop  of  ferric  chloride  solution  and  3  c.c. 
of  sodium  hydroxide  solution,  heating  the  liquid 
slightly,  and  then  acidifying  it  with  hydrochloric 
acid,  it  should  not  give  a  blue  coloration  (potassium 
cyanide) . 

6.  When  10  c.c.  of  a  recently  prepared  5  per  cent, 
solution  are  treated  with  10  drops  of  freshly  made 
starch  paste  and  20  drops  of  sulphuric  acid,  no  blue 
coloration    should    appear    within    five    minutes 
(potassium  iodate). 

7.  The  aqueous  solution  should  not  give  a  blue 
coloration     with    potassium    ferrocyanide    (iron 
salts). 

8.  One  grm.  of  the  iodide  is  dissolved  in  5  c.c.  of 
10  per  cent,  sodium  hydroxide  solution,  0-5  grm. 
of  zinc  dust  added,  and  the  liquid  gently  heated. 
There  should  be  no  evolution  of  ammonia,  recog- 
nisable by  its  odour  and  by  its  action  on  red  litmus 
paper  (nitrates). 


POTASSIUM  NITRATE. 
KN03  =  loi-n. 

1.  A  solution  of  the  salt  acidified  with  nitric  acid 
should  not  give  a  turbidity  with  barium  chloride 
(sulphates)  or  with  silver  nitrate  (chlorides). 

2.  The  solution  rendered  alkaline  with  ammonia, 
and  treated  with  ammonium  chloride  and  ammo- 
nium oxalate,  should  not  give  a  white  precipitate 
(calcium  salts),  whilst  the  filtrate  from  any  precipi- 
tate should  not  become  turbid  on  the  addition  o'f 
sodium  phosphate  (magnesium). 

40 


TESTS  OF  PURITY. 

3.  When  the  salt  is  treated  with  alcohol  and  the 
alcoholic  extract  is  evaporated  it  should  not  leave 
a  residue  which  imparts  a  yellow  coloration  to  a 
flame  (sodium  nitrate). 

4.  On  treating  the  solution  with  potassium  iodide, 
starch  paste,  and  dilute  sulphuric  acid  it  should  not 
give  a  blue  coloration  (potassium  nitrite). 

5.  When    the    solution    is    treated    with    pure 
potassium  iodide,  starch  paste,  and  tartaric  acid 
it  should  not  give  a  blue  coloration  (potassium 
iodate). 

6.  The  solution  ought  not  to  change  when  treated 
with  hydrogen  sulphide  (heavy  metals),  nor  give  a 
blue  coloration  with  potassium  ferrocyanide  (ferric 
salts). 

7.  When  i  grm.  of  potassium  nitrate  is  gently 
ignited,  the  residue  dissolved  in  a  little  water,  and 
the  solution  acidified  with  nitric  acid  and  treated 
with  silver  nitrate,  no  white  turbidity  should  be 
produced  (potassium  chlorate  and  perchlorate). 


POTASSIUM  NITRITE. 
KN02  =  85. 

1.  On  treating  a  solution  of  the  salt  with  acetic 
acid,  evaporating  it  to  dryness  on  the  water-bath, 
and  dissolving  the  residue  in  a  little  water,  the 
solution,    acidified    with    sulphuric    acid,    should 
not   give   a   red   coloration    with    brucine,    or   a 
blue    coloration    with    diphenylamine   (potassium 
nitrate). 

2.  The  solution,  acidified  with  nitric  acid,  should 
not    give    a    precipitate    with    barium    chloride 
(sulphates),  nor  with  silver  nitrate  (chlorides). 

3.  Quantitative    Estimation. — This    is    effected 
volumetrically  by  titrating  the  nitrous  acid  with 
N/ioo  potassium  permanganate  solution. 

41  -1BNIA  COUEG 

PHARMACY 


REAGENTS  AND   REACTIONS. 

POTASSIUM  PERMANGANATE. 
KMN04  -  158-03. 

1.  A  solution  of  0*5  grm.  of  the  salt  in  25  c.c. 
of  water  is  boiled  with  3  c.c.  of  alcohol,  until  the 
liquid  above  the  precipitate  becomes  colourless. 
The  nitrate,  acidified  with  nitric  acid,  should  not 
become  turbid  on  the  addition  of  barium  chloride 
(sulphates),  or  of  silver  nitrate  (chlorides). 

2.  When  0-5  grm.  of  the  salt  is  treated  with 
5  c.c.  of  boiling  water,  the  liquid  decolorised  with 
oxalic  acid  and  filtered,  and  the  filtrate  treated 
with  2  c.c.  of  strong  sulphuric  acid  and  i  c.c.  of 
ferrous  sulphate  solution,  a  brown  ring  should  not 
be  formed  at  the  zone  of  contact  of  the  two  layers 
of  liquid  (nitrates). 

3.  Quantitative    Estimation. — This    is    effected 
volumetrically  by  titrating  the  permanganate  solu- 
tion with  N-oxalic  acid  solution,  or,  better,  with 
standard  ferrous  ammonium  sulphate  solution. 

POTASSIUM  PERSULPHATE. 
K2S2O8  =  270-34. 

1.  A  solution   of   the  salt  should  not   give    a 
precipitate,    in    the    cold,    with   barium    chloride 
(potassium  sulphate). 

2.  Quantitative     Estimation. — This     may     be 
effected  volumetrically  in  various  ways  : — (a)  On 
boiling  a  solution  for  a  long  time,  the  potassium 
persulphate  is  decomposed  into  neutral  (normal) 
sulphate  and  free  sulphuric  acid,  whilst  oxygen 
is  liberated.    The  sulphuric  acid  produced  may  be 
titrated  with  N-potassium  hydroxide  solution,  and 
calculated  into  the  corresponding  amount  of  per- 
sulphate.     (6)    The    solution    of    persulphate    is 

42 


TESTS  OF  PURITY. 

titrated  with  an  excess  of  a  standard  solution  of 
ferrous  sulphate,  and  the  excess  of  ferrous  salt  not 
oxidised  by  the  persulphate  then  titrated  with 
N/io  potassium  permanganate  solution,  (c)  The 
solution  of  potassium  persulphate  is  treated  with  a 
measured  excess  of  standard  oxalic  acid  solution 
in  presence  of  a  trace  of  silver  nitrate.  The  oxalic 
acid  is  decomposed  (with  liberation  of  carbon 
dioxide),  the  excess  of  oxalic  acid  is  titrated 
with  potassium  permanganate  solution,  and  the 
amount  of  persulphate  calculated  from  the 
result. 

POTASSIUM  THIOCYANATE. 
KCNS  -  97-1. 

1.  An  aqueous  solution  of  the  salt  (i  :  20)  ought 
not    to    give    a   turbidity   with   barium    chloride 
(sulphates),  nor  form  a  precipitate  on  the  addition 
of  ammonium  sulphide  (heavy  metals). 

2.  The   solution    (i  :  20)   should   remain    abso- 
lutely colourless  when  treated  with  dilute  hydro- 
chloric acid  (HC1  of  sp.  gr.  1-19,  i  c.c.  +  water 
10  c.c.),  and  not  give  a  red  coloration  (iron). 

3.  Quantitative    Estimation. — This    is    effected 
volumetrically  by  treating  the  solution  with  an 
excess  of  silver  nitrate  solution,   acidifying  the 
liquid  with  nitric  acid,  adding  ferric  ammonium 
alum  as  indicator,  and  titrating  the  excess  of  silver 
nitrate  with  N/io  potassium  thiocyanate  solution. 


SILVER  NITRATE. 

AgN03  =  169-89. 

i.  On  treating  i  c.c.  of  a  20  per  cent,  solution 
of   the  salt  with   15   c.c.   of   absolute   alcohol  it 
should  not  give  a  permanent  crystalline  precipitate 
43 


REAGENTS  AND   REACTIONS. 

(potassium  nitrate),  nor  a  white  turbidity  (silver 
chloride) . 

2.  One  c.c.  of  the  20  per  cent,  solution  treated 
with  5  c.c.  of  ammonia  solution  should  give  a  clear 
colourless  liquid — not  a  blue  coloration  (copper), 
or  white  turbidity  (bismuth,  lead). 

3.  The  solution  when  treated  with  excess  of 
hydrochloric    acid    and    filtered    should    yield    a 
filtrate  which  leaves  no  residue  when  evaporated 
on  the  water-bath  (foreign  salts). 

4.  A  few  drops  of  the  20  per  cent,  solution  are 
added  to  a  solution  of  o-i  grm.  of  potassium  iodide 
in   10  c.c.  of  water,  containing  starch  paste  and 
a  few  drops   of   dilute  sulphuric   acid.     A  blue 
coloration  should  not  immediately  appear  (silver 
nitrite) . 

5.  Quantitative    Estimation. — The    silver    may 
be  precipitated  as  silver  chloride,  and  the  precipi- 
tate ignited  and  weighed.    Or  it  may  be  estimated 
volumetrically     by     titration      with     N-sodium 
chloride    solution    or    N-potassium    thiocyanate 
solution  (Volhard). 


SODIUM  ACETATE. 
NaCjHA  +  3H2O  =  136-12. 

1.  Sodium    acetate   should   dissolve   in   strong 
sulphuric   acid   without   becoming   brown    (tarry 
substances). 

2.  A  5  per  cent,  solution  should  not  alter  when 
treated  with  hydrogen  sulphide  (heavy  metals). 

3.  The  5  per  cent,  solution,  acidified  with  nitric 
acid,   should  not  give   a  turbidity  with  barium 
chloride     (sulphates),     nor     with     silver     nitrate 
(chlorides).     Nor  should  it,  when  acidified  with 
acetic    acid,  give    a    turbidity    with    ammonium 
oxalate  (calcium  salts). 

44 


TESTS   OF   PURITY. 

°f     Pi^Jr 

4.  A  5  per  cent,  solution  acidified  wit 

chloric  acid  should  not  give  a  blue  coloration 
when  treated  with  a  few  drops  of  potassium 
ferrocyanide  (ferric  salts). 


SODIUM  BROMIDE. 
NaBr  =  103. 

1.  On  introducing  a  crystal  of  the  salt  into  a 
colourless   gas   flame,  a  violet    coloration,   more 
visible  when  viewed  through  cobalt  glass,  should 
not  be  obtained. 

2.  All  the  other  tests  are  the  same  as  those 
given  for  potassium  bromide. 

3.  Quantitative  Estimation. — Since  commercial 
bromine    always    contains    a    small    amount    of 
chlorine  a   certain   proportion   of    chlorine   may 
also  be  tolerated  in  sodium  bromide,  but  it  must 
not  exceed  i  per  cent.     The  bromide  is  estimated 
as  follows  : — Three  grms.  of  the  previously  dried 
and   anhydrous   salt    are    dissolved   in    100   c.c. 
of  water,  and  10  c.c.  of  this  solution  are  titrated 
with  N/io  silver  nitrate  solution  in  presence  of  a 
few  drops  of  potassium  chromate  solution.    They 
should  consume  not  more  than  29-3  c.c.  of  the  silver 
solution.      Under    these    conditions    the    sodium 
bromide  would  contain   about  0-8  per  cent,   of 
sodium  chloride. 


SODIUM  CARBONATE. 
NaaCO.,  +  ioH2O  =  286-16. 

i.  On  evaporating  20  grms.  of  the  salt  in   a 
platinum  basin  with  an  excess  of  dilute  hydro- 
chloric acid,  drying  the  residue  for  some  hours  at 
45 


REAGENTS  AND   REACTIONS. 

120°  C.,  and  then  dissolving  it  in  water  acidified 
with  hydrochloric  acid,  a  clear  solution  free  from 
a  white  flocculent  deposit  should  be  obtained 
(absence  of  silicic  acid). 

2.  The  solution,  acidified  with  nitric  acid,  should 
not  give  a  precipitate  with  silver  nitrate  (chlorides) , 
nor    with    barium    chloride    (sulphates).      When 
acidified  with  hydrochloric  acid  it  should  not  give 
a  turbidity  or  precipitate  with  hydrogen  sulphide 
(heavy   metals),    even    after   neutralisation    with 
ammonia  (iron,  manganese). 

3.  The  solution  when  treated  with  hydrochloric 
acid  should  not  emit  hydrogen  sulphide,  recog- 
nisable by  its  darkening  action  on  lead  acetate 
paper  (absence  of  sodium  sulphide) . 

4.  The   solution   should   be   clear    (absence   of 
calcium    salts),    and    should    not    yield    a   white 
precipitate  on   the   addition   of   a  few   drops   of 
potassium  nitrite   solution   and  sufficient  hydro- 
chloric acid  to  make  the  liquid  acid  (absence  of 
thiosulphate) . 

5.  The  solution,  neutralised  with  hydrochloric 
acid,  should  not  give  a  red  coloration  with  ferric 
chloride  (thiocyanates) . 

6.  The  solution,  when  acidified  with  hydrochloric 
acid  and  then  treated  with  an  excess  of  pure  con- 
centrated potassium  hydroxide  solution,  should  not 
give  a  white  precipitate  soluble  in  excess  of  the 
reagent,  and  reprecipitated  by  ammonium  chloride 
(alumina) . 

7.  On  heating  the  solution  with  pure  sodium 
hydroxide  no  odour  of  ammonia  should  be  per- 
ceptible (ammonium  salts). 

8.  When  the  solution  is  tested  with  pure  sulphuric 
acid  in  Marsh's  apparatus  arsenical  spots  or  rings 
should  not  be  obtained  (arsenic). 

9.  Quantitative  Estimation. — A  solution  of  the 
salt  is  titrated  while  hot  with  N/io  oxalic  acid 
solution,  litmus  tincture  being  used  as  indicator. 

46 


TESTS   OF  PURITY. 

SODIUM   HYDROXIDE. 
NaOH  =  40. 

The  tests  of  purity  are  the  same  as  those  given 
for  potassium  hydroxide. 

SODIUM  HYPOCHLORITE. 

NaOCl  =  74-5. 

i.  The  main  test  to  be  applied  is  the  estimation 
of  the  active  chlorine.  For  this  purpose  a  definite 
quantity  of  the  hypochlorite  is  decomposed  with 
hydrochloric  acid,  an  excess  of  potassium  iodide 
added  to  the  liquid,  and  the  liberated  iodine 
titrated  with  N/io  sodium  thiosulphate  solution  in 
presence  of  starch  paste.  The  solution  of  hypo- 
chlorite, acidified  with  hydrochloric  acid,  may  also 
be  estimated  volumetrically  by  means  of  N/io 
arsenious  acid  solution,  starch  iodide  paper  being 
used  as  indicator. 

SODIUM   NITRATE. 

NaN03  =  85. 

1.  A  crystal  of  the  salt,  when  introduced  into  a 
colourless  gas  flame,  should  not  give  a  violet  colora- 
tion, more  visible  through  cobalt  glass  (potassium 
nitrate). 

2.  An  aqueous  solution  (i  :  20)  should  not  alter 
when    treated    with    hydrogen    sulphide    (heavy 
metals),  nor  give  a  precipitate  with  barium  chloride 
(sulphate)  or  silver  nitrate  (chlorides),  nor  when 
rendered  alkaline  with  ammonia  should  it  give  a 
precipitate  with  ammonium  oxalate  (calcium  salts). 

47 


REAGENTS  AND   REACTIONS. 

3.  The  solution  should  not  become  blue  when 
treated  with  pure  potassium  iodide  and  starch 
paste  (sodium  nitrite  or  iodate). 


SODIUM  NITRITE. 
NaNO2  =  69. 

The  tests  to  be  applied  are  the  same  as  in  the 
case  of  potassium  nitrite. 

SODIUM   NITROPRUSSIDE. 

Na2Fe(NO)  (CN)5  +  2H2O  -  298. 

i.  An  aqueous  solution  (i :  50)  of  the  salt, 
acidified  with  hydrochloric  acid,  should  not  give  a 
turbidity  with  barium  chloride  (sulphates). 


SODIUM  PHOSPHATE   (DISODIUM 
PHOSPHATE). 

Na2HPO4  +  i2H2O  =  358-30. 

1.  A  crystal  should  not  impart  a  violet  coloration, 
visible  through  cobalt  glass,  to  a  colourless  gas 
flame  (potassium  salts). 

2.  On    shaking    i    grm.     of    the    dehydrated 
powdered  salt  with  3  c.c.  of  Bettendorf  s  reagent, 
no  brown  coloration  should  appear  within  an  hour 
(arsenic). 

3.  The  aqueous  solution  should  not  be  changed 
by  hydrogen  sulphide  (heavy  metals),  nor,  when 
acidified,  should  it  emit  carbon  dioxide  (sodium 
carbonate) . 

4.  The  aqueous  solution,  acidified  with  nitric 
acid,  should  not  give   a  turbidity  with  barium 

48 


TESTS  OF   PURITY. 

chloride     (sulphates),     or     with     silver     nitrate 
(chlorides) . 

5.  On  dissolving  2  grms.  of  the  salt  in  10  c.c.  of 
water,  acidifying  the  solution  with  dilute  sulphuric 
acid,  and  adding  2  drops  of  a  dilute  solution  of 
indigo  and  10  c.c.  of  strong  sulphuric  acid,  the 
solution  should  retain  its  blue  colour  for  a  long  time 
(absence  of  nitrates). 

6.  Quantitative  Estimation. — The  acid  is  esti- 
mated   gravimetrically    by    precipitation     with 
magnesia  mixture,  or  volumetrically  by  titration 
with  uranyl  acetate  solution  (see  Phosphoric  Acid). 


SULPHURIC  ACID. 
H2SO4  =  98-08. 

1.  On  evaporating  and  igniting  10  grms.  of  the 
acid  in  a  platinum  dish,  no  residue  should  be  left 
(fixed  substances) . 

2.  When  diluted  with  10  volumes  of  water  the 
acid  should  not  become  turbid,  nor  yield  a  white 
precipitate  soluble  in  basic  ammonium  tartrate 
solution  (absence  of  lead  sulphate). 

3.  It  should  not  decolorise  a  few  drops  of  a 
o-i  per  cent,  solution  of  potassium  permanganate, 
nor  give  a  blue  coloration  when  diluted  and  treated 
with  a  few  drops  of  potassium  iodide  solution  and 
starch  paste  (absence  of  nitrous  gases) . 

4.  The  dilute  acid,  when  treated  with  an  excess 
of  barium  chloride  and  filtered,  should  not  give  a 
fresh  precipitate  on  the  addition  of  chlorine  water 
(sulphurous  anhydride). 

5.  It  should  not  yield  arsenical  spots  or  rings 
when  tested  in  Marsh's  apparatus,  nor,  when  diluted 
with  an  equal  volume  of  water,  should  it  give  a 
brown  coloration  with  Bettendorf 's  reagent  (absence 
of  arsenic). 

R.R.  49  4 


REAGENTS   AND   REACTIONS. 

6.  It    should    not,  when    diluted    with    water, 
decolorise  a  dilute  solution  of  indigo,  nor  give  a  red 
coloration  with  brucine  (nitric  acid). 

7.  It  should  not  give  a  precipitate  with  silver 
nitrate   chlorides). 

8.  On  adding  to  the  dilute  acid  twice  its  volume 
of  water  and  half  its  volume  of  a  saturated  solution 
of  sulphur  dioxide,  it  should  not  give  a  red  colora- 
tion (absence  of  selenious  acid). 

9.  The  acid,  diluted  with  10  volumes  of  water, 
should  not  give  a  turbidity  or  precipitate  with 
hydrogen    sulphide,   nor   should    it   do   so   after 
neutralisation  with  ammonia  (absence  of  heavy 
metals). 

10.  Quantitative    Estimation. — Sulphuric    acid 
may  be  estimated  gravimetrically  as  barium  sul- 
phate or  volumetrically  by  titration  with  standard 
sodium  hydroxide  solution,  with  phenolphthalein 
or  methyl  orange  as  indicator. 


TARTARIC  ACID. 

C4H6O6  =  150-05. 

1.  Tartaric  acid  should  be  colourless,  and  when 
ignited  on  platinum  should  leave  no  residue  (fixed 
mineral  substances). 

2.  It  should  be  completely  soluble  in  water  and 
in  three  times  its  weight  of  90  per  cent,  alcohol. 

3.  The  solution,  nearly  neutralised  with  ammo- 
nia, should  not  give  a  precipitate  or  turbidity  with 
hydrogen  sulphide  (absence  of  heavy  metals) . 

4.  The  solution,  acidified  with  nitric  acid,  should 
not   give   a   turbidity   either  with  silver  nitrate 
(chlorides)  or  barium  chloride  (sulphates) ,  or,  after 
neutralisation    with    ammonia,    with    ammonium 
oxalate  (calcium). 

5.  On    adding    an    equal    volume    of    calcium 

50 


TESTS   OF   PURITY. 

sulphate  to  the  solution,  which  has  been  nearly 
neutralised  with  ammonia,  there  should  be  no  tur- 
bidity (oxalic  or  racemic  acid). 

6.  On  treating  the  solution  with  milk  of  lime  in 
excess,  and  filtering  the  liquid,  the  filtrate  should 
not  become  turbid  when  boiled  (citric  acid). 

7.  Quantitative    Estimation. — This    is    effected 
volumetrically  by  titration  with  N-potassium  or 
sodium  hydroxide  solution  in  presence  of  phenol 
phthalein. 

TIN    CHLORIDE    (STANNOUS    CHLORIDE). 
SnCl2  +  2H2O  =  225. 

1.  The  crystals  should  be  colourless,  and  not  of 
a  yellow  tint  (iron)  or  milky.    They  should  dissolve 
in  water  or  alcohol  acidified  with  hydrochloric  acid, 
to  form  a  clear  solution. 

2.  A  solution  of  i  part  of  the  salt  in  50  parts 
of  water  containing  hydrochloric  acid  should  not 
become  turbid  on  the  addition  of  barium  chloride 
(sulphates). 

3.  When  heated  with  potassium  hydroxide,  it 
should  not  emit  ammonia  (ammoniacal  salts). 

4.  On  treating  the  solution,  slightly  acidified 
with  hydrochloric  acid,  with  hydrogen  sulphide 
and  filtering  it  from  the  precipitate,  the  filtrate 
should  leave  no  residue  on  evaporation  (salts  of 
zinc,  magnesium  and  alkalies). 

5.  When  2  grms.  of  the  salt  are  boiled  for  some 
minutes  with  10  cc..  of  pure  concentrated  hydro- 
chloric acid,  the  liquid  should  remain  colourless, 
and  not  turn  brown  or  yield  a  flocculent  black 
deposit  (arsenic). 

6.  Quantitative  Estimation. — The  tin  may  be 
estimated  gravimetrically  as  tin  dioxide  or  metallic 
tin,  or  the  solution  may  be  titrated  with  N/io 
iodine  solution. 


REAGENTS  AND   REACTIONS. 

URANYL  ACETATE. 

U02(C2H302)2  +  2H20  =  424-6. 

1.  A  5  per  cent,  aqueous  solution  of  the  salt 
should  remain  clear  after  the  addition  of  ammonia 
and  ammonium  carbonate  in  excess  (metals  of  the 
alkaline  earths). 

2.  A  solution  of  5  grms  of  the  salt  in  5  c.c.  of 
hydrochloric  acid,  diluted  to  100  c.c.  should  not 
yield  any  precipitate  when  treated  with  a  current 
of  hydrogen  sulphide  (heavy  metals). 

3.  A  solution  of  the  salt   (i  :  20)   should  not 
give  a  turbidity  with  barium  chloride  (sulphates). 


ZINC  CHLORIDE. 
ZnCl2  =  136-30. 

1.  An    aqueous   solution    of    the   salt    (i  :  20), 
acidified  with  hydrochloric  acid,  should  not  become 
turbid   with   hydrogen   sulphide    (heavy  metals), 
or    with    barium    chloride    (sulphates),    and   on 
treating    the    aqueous    solution    with    hydrogen 
sulphide  the  precipitate  should  be  perfectly  white, 
whilst  the  filtrate  should  leave  no  residue  when 
evaporated  (calcium,  magnesium,  alkali  salts) . 

2.  The  aqueous  solution  (i  :  20)  should  give  a 
white    precipitate    with    potassium   ferrocyanide, 
without  any  sign  of  red  (copper)  or  blue  coloration 
(iron) . 

3.  On  adding  to  a  clear  solution  of  i  grm.  of 
zinc  chloride  in  i  c.c.  of  water,  6  c.c.  of  90  per  cent, 
alcohol,  a  slight  flocculent  precipitate,  which  dis- 
appears on  the  addition  of  a  few  drops  of  hydro- 
chloric acid,  should  gradually  be  formed  (basic 
zinc  chloride). 

4.  Quantitative  Estimation. — The  zinc  in  the 

52 


TESTS   OF   PURITY. 

zinc  chloride  may  be  estimated  gravimetrically 
as  oxide  or  as  sulphide,  and  also  electrolytically. 


ZINC  SULPHATE. 
ZnS04  +  7H20  -  287-55. 

1.  An    aqueous    solution    of    the    salt    (i  :  10) 
should  remain  clear  when  treated  with  ammonia 
(lead,  aluminium,  iron),  and  colourless  (copper). 

2.  The  solution  should  not  emit  ammonia  when 
boiled  (ammonium  salts). 

3.  The  solution,  acidified  with  nitric  acid,  should 
not  become  turbid  on  the  addition  of  silver  nitrate 
(chlorides). 

4.  On  adding  a  solution  of  0-5  grm.  of  the  salt  in 
i  c.c.  of  water  to  2  c.c.  of  strong  sulphuric  acid 
and  i  c.c.  of  ferrous  sulphate  solution  a  black 
ring  should  not  be  formed  at  the  zone  of  contact 
of  the  two  liquids  (nitrates) . 

5.  The  solution,  acidified  with  hydrochloric  acid, 
should  not   yield   a  turbidity  or  precipitate   on 
treatment  with  hydrogen  sulphide  (lead,  copper, 
arsenic). 

6.  When  tested  in  Marsh's  apparatus,  it  should 
give  a  negative  result  (absence  of  arsenic) . 

7.  On  shaking  2  grms.  of  the  powdered  salt  with 
10  c.c.  of  absolute  alcohol,  and  filtering  the  liquid, 
the  filtrate  should  not  turn  blue  litmus  paper  red. 

8.  Quantitative  Estimation. — The  zinc  is  esti- 
mated gravimetrically  as  zinc  oxide. 


53 


REAGENTS   AND    REACTIONS. 


REAGENTS    AND    REACTIONS. 
A. 

ABELIN  (salvarsan  in  urine). — From  7  to  8  c.c.  of 
the  urine  are  acidified  in  a  test-tube  with  5  to 
6  drops  of  dilute  hydrochloric  acid,  and,  after 
cooling,  the  liquid  is  treated  with  3  to  4  drops 
of  0-5  per  cent,  sodium  nitrate  solution.  A  few 
drops  of  this  mixture  are  added  to  5  to  6  c.c.  of 
a  colourless  10  per  cent,  solution  of  resorcinol 
made  alkaline  with  sodium  carbonate.  In  the 
presence  of  salvarsan  a  pronounced  red  coloration 
appears  immediately. 

ADAMKIEWICZ  (proteins). — The  substance  under 
examination  is  dissolved  in  glacial  acetic  acid, 
and  concentrated  sulphuric  acid  is  gradually 
added  to  this  solution.  In  the  presence  of 
proteins  the  liquid  assumes  a  violet  coloration 
and  becomes  slightly  fluorescent. 

AGOSTINI  (dextrose  in  urine). — Five  drops  of  the 
urine  are  heated  with  5  drops  of  a  0-5  per  cent, 
solution  of  gold  chloride  and  3  drops  of  a  20  per 
cent,  solution  of  potassium  hydroxide.  A  red 
coloration  indicates  dextrose. 

ALESSANDRI-GANASSINI  (nitric  acid  and  nitrates). — 
The  reagent  consists  of  a  saturated  solution  of 
phenol  in  strong  hydrochloric  acid,  and  is  pre- 
pard  by  heating  the  two  substances  for  twelve 
hours  on  the  water-bath.  The  dry  residue  from 
the  substance  under  examination  is  treated  with 
10  drops  of  the  reagent  and  heated  on  the  water- 
bath.  In  the  presence  of  nitric  acid  a  violet 
coloration  is  obtained.  The  reaction  may  be 
rendered  more  sensitive  by  adding  to  the  violet 
liquid  a  few  drops  of  ammonia  solution,  which 
54 


REAGENTS   AND   REACTIONS. 

immediately  produce  an  intense  emerald-green 
coloration. 

ALESSANDRI-GANASSINI  (nitrites). — On  adding  a 
few  drops  of  a  mixture  of  3  parts  of  acetic  acid 
with  i  part  of  phenol  to  a  liquid  containing  a 
nitrite,  a  yellow  coloration,  which  becomes 
more  pronounced  after  slight  heating,  is  at 
once  obtained.  The  coloration  is  much  inten- 
sified by  adding  a  slight  excess  of  ammonia 
solution  to  the  liquid.  On  treating  the  liquid 
in  a  beaker  with  zinc  or  aluminium  dust  and  a 
fragment  of  potassium  hydroxide,  it  changes  first 
to  a  greenish  tint  and  finally  to  blue. 

ALFRAISE  (iodine). — The  liquid  under  examination 
is  treated  with  i  drop  of  a  reagent  prepared  as 
follows  : — To  10  c.c.  of  starch  paste  (i  :  100)  are 
added  o-i  grm.  of  potassium  nitrite  and  i  drop 
of  hydrochloric  acid.  In  the  presence  of  iodine 
the  well-known  blue  coloration  is  obtained. 

ALIAMET  (copper  salts). — An  addition  of  2  per  cent, 
of  pyrogallic  acid  is  made  to  a  cold  saturated 
solution  of  sodium  sulphite.  This  liquid  gives 
an  intense  blood-red  coloration  with  copper  salts, 

ALLEN  (stain  for  bacteriology). — An  addition  of 
o-i  per  cent,  of  methylene  blue  is  made  to  a 
7-5  per  cent,  solution  of  sodium  chloride,  and  the 
liquid  then  diluted  with  20  c.c.  of  water. 

ALLEN  (phenols). — Two  drops  of  hydrochloric  acid 
and  i  drop  of  nitric  acid  are  added  to  i  or  2  drops 
of  the  liquid  under  examination.  In  the  presence 
of  phenols,  a  cherry- red  coloration  is  obtained  on 
heating  the  liquid. 

ALLEN  (vegetable  fats) . — Equal  volumes  of  the  fat 
and  of  nitric  acid  (sp.  gr.  1-40)  are  shaken  for 
half  a  minute  and  allowed  to  stand  for  fifteen 
minutes.  In  the  presence  of  vegetable  fat  a 
coffee-brown  coloration  is  obtained. 

ALLEN  (strychnine). — The  ethereal  extract  of  the 
alkaloid  is  evaporated  by  causing  it  to  fall  drop  by 
55 


REAGENTS   AND   REACTIONS. 

drop  into  a  basin  on  the  water-bath,  and  the 
residue  is  treated  with  sulphuric  acid  and 
manganese  dioxide.  In  the  presence  of  strych- 
nine a  violet  coloration  is  obtained. 

ALLEN-GAND  (dextrose). — A  solution  of  8-7916  grms. 
of  electrolytic  copper  in  93  grms.  of  concentrated 
sulphuric  acid  diluted  with  an  equal  volume  of 
water  is  treated  with  sufficient  strong  ammonia 
solution  to  make  the  liquid  up  to  a  litre.  Ten  c.c. 
of  this  reagent  are  reduced  by  0-050  grm.  of 
dextrose. 

ALLEN-FRAN KEL  (adrenaline). — A  solution  of  adre- 
naline when  heated  with  iodic  acid,  or  with 
potassium  bi-iodate  and  phosphoric  acid  gives  a 
red  coloration. 

ALMEN  (albumin  in  urine). — Four  grms.  of  tannin 
are  dissolved  in  8  c.c.  of  25  per  cent,  acetic  acid 
and  in  190  c.c.  of  40  to  50  per  cent,  alcohol. 
This  reagent  also  precipitates  nucleo-albumin. 

ALMEN  (dextrose  in  urine). — Four  grms.  of  sodium 
potassium  tartrate  are  dissolved  in  100  grms.  of 
potassium  hydroxide  solution  (sp.  gr.  1-33),  and 
about  2  grms.  of  basic  bismuth  carbonate  are 
digested  in  the  cold  solution,  which  is  then  de- 
canted. On  heating  a  liquid  containing  dextrose 
with  this  reagent,  it  darkens  and  eventually  gives 
a  black  precipitate  (see  Bottger,  Nylander). 

ALPERS  (blood).- — The  reagent  consists  of  a  mixture 
in  equal  volumes  of  tincture  of  guaiacum  and  oil 
of  turpentine.  On  shaking  the  reagent  with  a 
concentrated  solution  of  blood,  the  milky  liquid 
turns  blue. 

ALPERS  (albumin  in  urine). — Albumin  is  precipi- 
tated from  urine  by  a  i  per  cent,  solution  of 
mercuric  succinimide. 

ALTMANN  (fixative  solution). — This  is  a  mixture  in 
equal  parts  of  a  5  per  cent,  solution  of  potassium 
bichromate  and  a  2  per  cent,  solution  of  osmic 
acid. 

56 


REAGENTS  AND   REACTIONS. 

AMAND  (scatol  in  urine). — Ten  c.c.  of  the  urine  are 
shaken  with  a  drop  of  sulphuric  acid,  2  c.c.  of 
chloroform,  and  2  c.c.  of  a  10  per  cent,  aqueous 
solution  of  sodium  persulphate.  The  chloroform 
is  coloured  blue  when  scatol  is  present. 

ANDERSON  (distinction  between  the  salts  of  quinoline 
and  of  pyridine}. — The  double  chlorides  of 
pyridine  and  platinum  are  converted,  when 
boiled  with  water,  into  insoluble  double  salts, 
with  the  liberation  of  hydrochloric  acid,  whilst 
the  corresponding  salts  of  quinoline  remain 
soluble. 

ANDREASH  (cystine). — A  hydrochloric  acid  solution 
of  cystine  is  treated  with  a  few  drops  of  a  solution 
of  ferric  chloride,  and,  immediately  afterwards, 
with  ammonia.  The  solution  assumes  a  red 
colour,  which  is  intensified  by  shaking  the  liquid 
in  contact  with  air. 

ANGELI  (hydroocylamine}. — The  solution  of  the  base 
or  of  one  of  its  salts  is  treated  with  a  few  drops 
of  a  solution  of  sodium  nitroprusside,  and  then 
rendered  strongly  alkaline  with  sodium  hydroxide 
and  heated.  A  magenta-red  coloration  is 
obtained.  The  presence  of  ammonium  salts 
interferes  with  the  reaction. 

APERY  (aloes}. — On  adding  a  drop  of  a  dilute 
solution  of  ferric  chloride  to  a  solution  containing 
aloes  (previously  decolorised  with  animal  char- 
coal) a  chestnut -brown  coloration  is  obtained. 
Sensitiveness,  i  :  3,000. 

ARATA  (coal-tar  colours  in  wine}. — The  colouring 
matters  are  extracted  from  the  acidified  wine  by 
boiling  it  with  wool  which  has  been  freed  from 
fat.  They  are  identified  by  submitting  the 
fibres  of  the  wool  to  various  tests. 

ARCHETTI    (caffeine}. — A    solution    of    potassium 

ferrocyanide,  when  heated  to  boiling  with  half  its 

volume  of  nitric  acid,   and  then  diluted  with 

water,  gives  a  precipitate  of  Prussian  blue  in  the 

57 


REAGENTS  AND   REACTIONS. 

presence  of  caffeine.  The  reaction  is  also  given 
by  uric  acid. 

ARMANI-BARBONI  (caffeine). — On  boiling  for  two 
to  three  minutes  a  minute  quantity  of  caffeine 
with  potassium  hydroxide  solution,  cooling  the 
liquid,  and  adding  a  small  amount  of  Wellman's 
reagent  (sodium  phosphomolybdate)  and  then  a 
few  drops  of  50  per  cent,  potassium  hydroxide 
solution,  a  brilliant  blue  coloration  resembling 
that  of  Fehling's  solution  is  obtained.  A 
similar,  though  less  intense,  reaction  is  obtained 
with  sodium  phosphotungstate.  The  reaction  is 
not  given  by  theobromine. 

ARMANI-BARBONI  (nitrates). — The  reagent  consists 
of  a  saturated  solution  of  benzidine  in  dilute 
acetic  acid.  In  the  presence  of  nitrites,  an  orange- 
yellow  coloration  is  obtained,  which  becomes 
more  intense  on  standing.  In  applying  the  test 
4  to  5  drops  of  the  reagent  are  added  to  10  c.c.  of 
the  liquid  under  examination. 

ARNOLD  (aceto-acetic  acid  in  urine). — The  reagent 
consists  of  2  parts  of  a  solution  of  i  grm.  of  para- 
amino-aceto-phenone  in  80  to  100  c.c.  of  water 
with  the  addition  of  a  few  drops  of  hydrochloric 
acid  to  clear  the  liquid,  and  of  I  part  of  a  i  per 
cent,  solution  of  sodium  nitrite.  In  applying 
the  test  equal  parts  of  the  reagent  and  of  the 
urine  are  treated  with  2  to  3  drops  of  strong 
ammonia  solution,  which  produces  an  intense 
red-brown  coloration.  On  now  adding  to  i  part 
of  this  mixture  10  to  12  volumes  of  strong  hydro- 
chloric acid,  there  is  formed  in  the  presence  of 
aceto-acetic  acid  a  violet-purple  coloration  and 
sometimes  a  yellow  coloration. 

ARNOLD  (lactic  acid  in  gastric  juice) . — The  following 
solutions  are  used  : — (i)  An  alcoholic  solution 
of  o-i  grm.  of  gentian  violet  in  250  c.c.  of  water ; 
(2)  an  aqueous  solution  of  ferric  chloride  (5  :  20). 
One  c.c.  of  the  second  solution  is  mixed  with  a 

58 


COLUflf 

f 


REAGENTS   AND 

few  drops  of  the  first,  and  the  filtered  gastric 
juice  is  added  drop  by  drop  to  the  mixture.  If 
lactic  acid  is  present,  a  yellowish-green  coloration 
is  obtained. 

ARNOLD  (alkaloids}.  —  (i)  Certain  alkaloids  give 
distinctive  colorations  when  heated  on  the  water- 
bath  with  syruppy  phosphoric  acid  (prepared  by 
dissolving  metaphosphoric  acid  and  phosphoric 
anhydride  in  officinal  phosphoric  acid),  as,  for 
example  :  aconitine,  violet  ;  nicotine,  yellow  ; 
cocaine,  green.  (2)  Many  alkaloids  give  dis- 
tinctive colorations  when  triturated  with  strong 
sulphuric  acid,  and  then  treated  with  a  30  to 
40  per  cent,  alcoholic  solution  of  potassium 
hydroxide. 

ARNOLD  (narceine).  —  A  red  coloration  is  obtained 
on  heating  narceine  with  strong  sulphuric  acid 
and  a  trace  of  phenol. 

ARNOLD-VITALI  (alkaloids).  —  A  small  quantity  of 
the  alkaloid  is  ground  up  with  strong  sulphuric 
acid,  a  crystal  of  sodium  nitrite  added,  and  sub- 
sequently some  alcoholic  potassium  hydroxide 
solution  (30  to  40  per  cent.).  Many  alkaloids 
give  distinctive  colorations.  For  example, 
atropine  and  homatropine  give  an  orange-yellow 
coloration,  which,  on  the  addition  of  potassium 
hydroxide,  changes  to  reddish-violet  and  finally 
to  pink. 

ARNOLD-WERNER  (phenol).  —  A  solution  of  phenol, 
when  rendered  slightly  alkaline  with  ammonia, 
and  boiled  with  bromine,  gives  a  blue  coloration. 
Under  ,the  same  conditions  w-cresol  gives  a  bluish 
green  coloration,  />-cresol  no  coloration,  and 
o-cresol  a  blue  coloration. 

ARZNBERGER  (essential  oil  of  peppermint).  —  On 
heating  i  drop  of  this  essential  oil  with  i  c.c.  of 
formaldehyde  a  pink  coloration  is  obtained  ;  this 
does  not  appear  with  menthol,  nor  with  the  oil  of 
other  varieties  of  mint.  When  the  liquid  is 
59 


REAGENTS  AND   REACTIONS. 

treated  with  glacial  acetic  acid,  the  colour 
becomes  red,  then  violet,  and  finally  brown. 
AYMONIER  (a-naphthol). — A  15  per  cent,  alcoholic 
solution  of  a-naphthol  gives  a  violet-coloration 
when  mixed  with  sugar  and  twice  its  volume  of 
sulphuric  acid.  On  treating  the  alcoholic  solu- 
tion of  a-naphthol  with  i  drop  of  a  mixture  of 
i  part  of  potassium  bichromate,  10  parts  of 
water,  and  i  part  of  nitric  acid,  a  black  precipi- 
tate is  obtained.  This  reaction  is  not  given  by 
/2-naphthol. 


B. 

BACH  (hydrogen  peroxide). — Two  solutions  are  pre- 
pared, the  first  containing  0-03  grm.  of  potas- 
sium bichromate  and  5  drops  of  aniline  in  a  litre 
of  water  ;  the  second  5  grms.  of  oxalic  acid  in 
100  c.c.  of  water.  On  shaking  5  c.c.  of  hydrogen 
peroxide  with  5  c.c.  of  the  first  solution  and 
i  drop  of  the  second,  a  reddish- violet  coloration 
is  obtained.  Sensitiveness  i  :  400,000. 

BACH  (copper  salts). — The  reagent  consists  of  a 
mixture  in  equimolecular  parts  of  20  per  cent, 
formaldehyde  and  hydroxylamine  hydro  chloride. 
In  the  presence  of  a  trace  of  copper  salts,  pre- 
viously treated  with  potassium  hydroxide,  it 
gives  a  violet  coloration. 

BAECCHI  (blood). — An  aqueous  solution  of  alizarine 
blue  S  is  diluted  with  water  until  it  appears  of  a 
yellow  colour.  Two  c.c.  of  this  solution  are 
shaken  with  I  c.c.  of  hydrogen  peroxide,  and  the 
liquid  to  be  tested  is  poured  down  the  side  of  the 
test-tube.  In  the  presence  of  blood,  an  intense 
blue  coloration  will  be  produced  in  the  upper  part 
of  the  tube. 

BAEME  (tannin). — A  solution  containing  i  grm.  of 
sodium  tungstate  and  2  grms.  of  sodium  acetate 
60 


REAGENTS  AND   REACTIONS. 

in  10  c.c.  gives  an  insoluble  yellow  precipitate 
with  tannin  in  acid  or  alkaline  solution. 

BAEYER  (dextrose).— On  boiling  a  solution  of 
dextrose  with  orthonitrophenylpropionic  acid 
and  sodium  hydroxide,  a  blue  coloration  (due  to 
the  formation  of  indigo)  is  obtained. 

BAEYER  (indol). — An  aqueous  solution  of  indol 
gives  a  red  coloration,  and  then  a  red  precipitate, 
on  treatment  with  fuming  nitric  acid. 

BARBOT  (fatty  oils). — On  treating  200  grms.  of 
the  oil  with  2  grms.  of  fuming  nitric  acid  satu- 
rated with  oxides  of  nitrogen,  the  mixture 
assumes  various  colours,  according  to  the  nature 
of  the  oil.  In  the  case  of  olive  oil,  the  mixture 
is  white,  and,  after  an  hour,  a  solid  product 
separates. 

BARFOED  (dextrose). — A  solution  of  14  grms.  of 
crystalline  copper  acetate  in  200  c.c.  of  water 
and  5  c.c.  acetic  acid  is  reduced  by  dextrose  at 
the  ordinary  temperature,  and  more  rapidly  on 
heating.  Dextrin,  lactose,  and  cane  sugar  do 
not  give  this  reaction. 

BARRALET  (hydrogen  peroxide). — On  adding  hydro- 
gen peroxide  to  a  mixture  of  potassium  ferro- 
cyanide  and  a  ferrous  salt,  Prussian  blue  is 
obtained. 

BASCH  (sesame  oil  in  olive  oil). — One  c.c.  of  the  oil 
is  dissolved  in  I  c.c.  of  petroleum  spirit,  and  the 
solution  treated  with  an  equal  volume  of  sul- 
phuric acid  containing  a  third  of  its  volume  of 
hydrogen  peroxide  (the  mixture  must  have  been 
made  in  the  cold).  The  tube  is  shaken  two  or 
three  times  and  allowed  to  stand.  In  the  presence 
of  sesame  oil,  a  green  ring  appears  at  the  zone  of 
contact  of  the  two  liquids,  the  petroleum  spirit 
layer  being  coloured  brown. 

BAUDOUIN  (sesame  oil). — On  shaking  2  parts  of 
the  oil  with  i  part  of  a  solution  of  i  grm.  of  cane 
sugar  in  10  c.c.  of  hydrochloric  acid  (sp.  gr.  1-18) 

61  C0 -- 


REAGENTS  AND   REACTIONS. 

a  pink  coloration  is  obtained  in  the  presence  of 
sesame  oil. 

BAUER  (solanine}. — A  solution  of  telluric  acid  in 
sulphuric  acid  gives  a  red  coloration  when 
heated  with  a  faint  trace  of  solanine. 

BAUMANN-GOLDMANN  (cystine). — A  sodium  hy- 
droxide solution  of  cystine  gives  a  voluminous 
precipitate  when  shaken  with  benzoyl  chloride. 

BECHI  (cotton  seed  oil). — (a)  A  solution  of  i  grm.  of 
silver  nitrate  in  5  c.c.  of  water  is  diluted  to 
200  c.c.  with  96  per  cent,  alcohol ;  (b)  85  grms. 
of  amyl  alcohol  are  mixed  with  15  grms  of  colza 
oil.  Ten  c.c.  of  the  oil  under  examination  are 
shaken  with  i  c.c.  of  the  solution  (a)  and  then 
with  10  c.c.  of  solution  (b),  and  the  mixture 
heated  for  ten  minutes  on  the  water-bath.  A 
brown  coloration  is  produced  in  the  presence  of 
cotton  seed  oil. 

BEHRENS  (fatty  oils). — On  shaking  an  oil  with 
equal  volumes  of  strong  sulphuric  and  nitric 
acids  solidification  may  take  place,  and  various 
colorations  are  obtained,  according  to  the  nature 
of  the  oil. 

BEISSENHIRTZ  (aniline). — A  solution  of  aniline  in 
strong  sulphuric  acid  gives  first  a  red  and  then  a 
blue  coloration  on  treatment  with  potassium 
bichromate. 

BELA  VON  BITTO  (aldehydes  and  ketones). — A  few 
c.c.  of  a  0-5  to  i  per  cent,  aqueous  or  alcoholic 
solution  of  a  salt  of  metadiamine  are  added 
to  the  solution  under  examination.  In  the 
presence  of  aldehydes  or  ketones,  there  will  be 
produced,  after  a  few  minutes,  a  magnificent 
green  fluorescence,  which  disappears  on  rendering 
the  liquid  alkaline  and  reappears  on  acidification. 

BELLIER   (sesame  oil). — (i)    When  sesame   oil  is 

shaken  with  a  solution  of  2  grms.  of  sodium 

vanadate  in  100  c.c.  of  sulphuric  acid  and  50  c.c. 

of  water  an  intense  green  coloration,  changing 

62 


REAGENTS  AND   REACTIONS. 

to  black,  is  obtained.  (2)  On  shaking  a  mixture 
of  100  c.c.  of  sulphuric  acid,  50  c.c.  of  water, 
and  100  c.c.  of  a  40  per  cent,  solution  of  formalde- 
hyde with  an  equal  volume  of  the  oil,  an  emulsion 
of  a  pronounced  blue-black  colour  is  produced. 
(3)  Two  c.c.  of  the  oil  are  shaken  with  2  c.c.  of 
crystallised  benzene  saturated  with  resorcinol 
and  2  c.c.  of  nitric  acid  (sp.  gr.  1-38)  free  from 
nitrous  fumes,  and  the  appearance  of  the  upper 
oily  layer  and  the  lower  acid  layer  is  noted.  In 
the  presence  of  sesame  oil,  the  mixture  becomes 
intense  blue,  whilst  the  acid  which  separates 
assumes  an  intense  bluish-green  coloration, 
which  is  not  very  permanent,  although  it 
persists  for  at  least  five  minutes. 

BERLINERBLAU  (dulcine). — A  small  quantity  of  the 
substance  is  mixed  with  2  to  3  drops  of  pure 
phenol  and  an  equal  quantity  of  strong  sul- 
phuric acid,  and  the  mixture  is  heated  for  some 
time  at  the  boiling  temperature.  After  cooling, 
the  liquid  is  diluted  and  cautiously  treated  with 
sodium  hydroxide  solution  so  as  to  form  two 
layers.  At  the  zone  of  contact  there  is  formed  a 
blue  ring,  which  becomes  more  intense,  and 
gradually  extends  to  the  alkaline  liquid. 

BERTHELOT  (phenol). — On  adding  a  small  quantity 
of  a  solution  of  sodium  or  calcium  hypochlorite 
to  the  liquid,  which  has  been  made  slightly 
alkaline,  and  heating  the  mixture,  a  blue 
coloration,  changing  to  red  on  acidification,  is 
obtained  when  phenol  is  present. 

BERTRAND  (alkaloids). — Silicotungstic  acid  (5  per 
cent,  solution  of  sodium  silicotungstate)  gives 
with  solutions  of  alkaloids,  in  presence  of  hydro- 
chloric acid,  precipitates,  which  are  flocculent, 
gelatinous,  powdery  or  crystalline,  and  of 
various  colours,  according  to  the  nature  of  the 
alkaloid. 

BERZELIUS  (proteins). — A  recently-prepared  con- 
63 


REAGENTS  AND  REACTIONS. 

centrated  solution  of  metaphosphoric  acid 
precipitates  all  the  proteins  from  their  aqueous 
solutions. 

BEST  (glycogen). — A  solution  of  i  grm.  of  carmine 
with  2  grms.  of  ammonium  chloride  and  0-5  grm. 
of  lithium  carbonate  in  50  c.c.  of  water  gives  a 
coloration  at  the  zone  of  contact. 

BETTENDORF  (arsenic). — A  solution  of  stannous 
chloride  saturated  with  gaseous  hydrochloric 
acid  produces  in  the  hot  liquid  under  examina- 
tion a  brown  coloration  or  a  black  precipitate  of 
metallic  arsenic,  provided  that  no  oxidising 
substances  are  present. 

BIAL  (pentoses  in  urine). — A  solution  of  1-5  grm.  of 
orcinol  in  500  c.c.  of  hydrochloric  acid  (30  per 
cent.)  is  treated  with  a  few  drops  of  a  10  per 
cent,  solution  of  ferric  chloride.  On  heating  to 
boiling  point  a  small  quantity  of  the  urine  with 
5  drops  of  this  reagent,  a  green  coloration 
indicates  pentoses. 

BIEBER  (almond  oil). — Five  parts  of  the  oil  are 
shaken,  in  the  cold,  with  i  part  of  a  mixture  in 
equal  proportions  of  sulphuric  acid  (puriss.,  of 
66°  Be.)  and  fuming  nitric  acid  (sp.  gr.  1*42). 
Pure  almond  oil  forms  a  yellowish  emulsion, 
changing  after  some  time  to  red,  whilst  peach- 
kernel  oil  forms  a  fugitive  purple  emulsion, 
which  soon  changes  to  orange,  and  then  to 
brown. 

BIEL  (cocaine). — A  solution  of  o-i  grm.  of  cocaine 
hydrochloride  in  i  c.c.  of  strong  sulphuric  acid 
is  heated  for  some  minutes  on  the  water-bath, 
and  99  c.c.  of  water  then  added.  Under  these 
conditions,  benzoic  acid  is  precipitated  as  a  white 
crystalline  mass. 

BIFFI  (biliary  pigments). — The  urine  (100  c.c.)  is 
acidified  with  sulphuric  acid,  and  then  treated, 
little  by  little,  with  30  drops  of  a  5  per  cent, 
solution  of  barium  chloride.  The  liquid  is 


REAGENTS  AND   REACTIONS. 

decanted  while  still  turbid,  and  immediately 
poured  on  to  dry  absorbent  cotton  on  a  sheet  of 
glass,  and  in  the  middle  of  this  is  placed  a  crystal 
of  potassium  bichromate.  If  the  urine  contains 
biliary  pigments,  even  in  small  quantity,  a 
green  ring  will  appear  and  gradually  spread, 
whilst  in  the  vicinity  of  the  crystal  a  blue  ring, 
changing  to  red,  will  be  formed. 

BISCHOFF  (biliary  acids). — Biliary  acids  give  a  red 
coloration  when  heated  with  dilute  sulphuric 
acid  and  cane  sugar. 

BISHOP  (sesame  oil}. — On  shaking  equal  volumes 
of  hydrochloric  acid  and  sesame  oil  which  has 
been  exposed  to  the  light  for  twenty-four  hours 
the  acid,  which  separates  after  standing, 
gradually  assumes  a  bluish-green  coloration. 

BLAREZ  (coal-tar  colours  in  wine}. — Twenty  c.c.  of 
the  wine  are  shaken  for  a  minute  with  5  grms. 
of  lead  peroxide  and  filtered.  Natural  colouring 
matters  of  the  wine  disappear,  whilst  coal-tar 
colours  remain. 

BOAS  (hydrochloric  acid  in  gastric  juice). — The 
reagent  consists  of  a  solution  of  I  grm.  of 
resorcinol  and  3  grms.  of  sugar  in  100  c.c.  of 
50  per  cent,  alcohol.  The  liquid  to  be  tested  is 
mixed  with  a  few  drops  of  the  reagent  and 
evaporated.  In  the  presence  of  hydrochloric 
acid  a  red  coloration  will  be  obtained. 

BOAS  (lactic  acid  in  gastric  juice). — The  test 
depends  on  the  oxidation  of  the  lactic  acid  to 
aldehydes  and  formic  acid  by  regulated  treat- 
ment with  maganese  dioxide  and  sulphuric  acid. 
The  aldehydes  are  recognised  by  the  formation 
of  iodoform  by  means  of  an  alkaline  solution  of 
iodine,  or  by  the  reaction  obtained  with  Nessler's 
reagent.  This  reaction  is  more  distinctive  than 
that  of  Uffellmann. 

BOCCHI  (filicic  acid). — On  treating  a  hot  solution 
of  filicic  acid  in  dilute  ammonium  hydroxide 

R.R.  65  5 


REAGENTS  AND   REACTIONS. 

with  hydrochloric  acid,  then  making  the  liquid 
alkaline  again  with  ammonia,  and  adding  a  trace 
of  a  solution  of  ferrous  and  ferric  chlorides,  a 
fine  violet  coloration  is  produced. 

BODDE  (differentiation  of  resorcinol  from  phenol, 
benzoic  acid,  and  salicylic  acid). — A  solution  of 
resorcinol  gives  with  sodium  hypochlorite  a  violet 
coloration,  changing  to  yellow  ;  on  the  addition 
of  more  hypochlorite,  or  on  heating,  a  yellowish- 
rose  coloration,  changing  to  brown,  is  obtained. 
By  adding  ammonia  before  the  hypochlorite 
there  is  produced  first  a  violet  and  then  a  yellow 
coloration,  which  on  heating  changes  to  dark 
green.  Phenol  and  benzoic  and  salicylic  acids 
give  only  a  slight  yellow  coloration  with  sodium 
hypochlorite,  and  that  only  on  heating  ;  on  the 
addition  of  ammonia  the  acids  give  no  colora- 
tion, whilst  phenol  gives  a  greenish-blue 
coloration. 

BODECKER  (albumin  in  urine}. — A  solution  of 
potassium  ferrocyanide,  added  to  a  liquid  con- 
taining albumin  and  acidified  with  acetic  acid, 
gives  a  turbidity  or  a  flocculent  precipitate. 

BOHMER  (stain  for  microscopy) . — (i)  Haematoxylin, 
i  grm.  in  10  c.c.  of  absolute  alcohol ;  (2)  ammo- 
nium alum  10  grms.  in  200  c.c.  of  water.  The 
two  solutions  are  mixed  and  filtered  after  a 
week. 

BONNEMA  (vanillin). — A  trace  of  vanillin  is  dis- 
solved in  a  few  c.c.  of  acetic  acid  containing 
10  per  cent,  of  hydrochloric  acid,  and  the  solu- 
tion is  treated  with  5  drops  of  essential  oil  of 
santal-wood.  A  cherry-red  coloration  is  ob- 
tained, which  becomes  violet  brown  on  heating, 
and  changes  to  green  after  twenty- four  hours. 

BORNSTEIN  (saccharin) . — The  saccharin  is  extracted 

with   ether,   the   ethereal  solution   evaporated, 

and   the   residue    heated   with    resorcinol    and 

strong  sulphuric  acid.    The  fused  mass  is  washed 

66 


REAGENTS  AND   REACTIONS. 

with  water  and  rendered  alkaline  with  potassium 
hydroxide.  Fluorescein  produced  from  the 
saccharin  causes  the  liquid  to  have  an  intense 
yellowish-green  fluorescence. 

BORNTRAGER  (aloes). — An  alcoholic  solution  of  the 
aloes  is  shaken  with  petroleum  spirit,  and  the 
extract  separated  and  shaken,  with  gentle 
warming,  with  a  few  drops  of  strong  ammonia 
solution.  A  violet  coloration  is  produced  in  the 
liquid.  This  reaction  is  also  given  by  rhubarb, 
turmeric,  and  catechu. 

BOTTGER  (nitrous  acid). — A  solution  of  i  grm.  of 
starch  in  200  c.c.  of  water  and  I  grm  of  hydro- 
chloric acid  is  neutralised  with  calcium  car- 
bonate, then  treated  with  10  grms  of  sodium 
chloride  and  0*5  grm.  of  cadmium  iodide,  and 
diluted  to  250  c.c.  In  the  presence  of  nitrous 
acid  a  blue  coloration  is  obtained. 

BOTTGER  (hydrogen  peroxide). — The  reaction  is 
based  upon  the  reducing  action  of  hydrogen 
peroxide  upon  ammoniacal  silver  oxide. 

BOTTGER  (animal  and  vegetable  fibres) . — The  fibres 
under  examination  are  dyed  with  an  alcoholic 
solution  of  rosolic  acid,  and  extracted  with 
sodium  hydroxide  solution  and  washed.  Animal 
fibres  then  show  a  rose  colour,  and  linen  red, 
whilst  cotton  remains  unaltered.  Or  the  fibres 
may  be  dyed  with  magenta,  and  washed  with 
water  and  extracted  with  ammonia  solution. 
Only  cotton  fibres  retain  the  colour  under  these 
conditions. 

BOTTGER  (dextrose  in  urine) . — On  boiling  a  solution 
containing  dextrose  with  a  solution  of  sodium 
carbonate  and  a  little  bismuth  subnitrate,  a 
dark  coloration  and  then  a  black  precipitate  is 
obtained. 

BOTTGER  (colouring  matters  in  wine). — The  wine  is 
diluted  with  nine  times  its  volume -of  fVftter,  L  p  t 
and  then  treated  with  a  third  of  its  voliimb  of 
67 


REAGENTS   AND   REACTIONS. 

a  concentrated  solution  of  copper  sulphate. 
Pure  wine  is  decolorised,  whilst  added  colouring 
matters,  such  as  mallow,  cherry  and  magenta 
remain  unaltered,  or  are  changed  to  violet. 

BOTTGER  (sugar  in  glycerin). — A  mixture  of 
5  drops  of  the  glycerin,  5  c.c.  of  water,  i  drop 
of  nitric  acid,  and  0-03  grm.  of  ammonium 
molybdate  is  heated  to  boiling.  If  sugar  is 
present  an  intense  blue  coloration  will  be 
produced. 

BOUCHARD  AT  (alkaloids). — A  solution  of  2  grms. 
of  iodine  and  4  grms.  of  potassium  iodide  in 
100  c.c.  of  water  gives  brown  precipitates  with 
alkaloids. 

BOUDET  (olive  oil) . — Olive  oil  (20  parts)  is  solidified 
by  treatment  with  i  part  of  fuming  nitric  acid 
containing  a  little  cane  sugar  or  starch  or  copper 
(elaidin  test). 

BOUGAULT  (antipyrin) . — Antipyrin  in  alcholic  solu- 
tion absorbs  iodine  when  treated  with  a  solution 
of  mercuric  chloride  (2-5  per  cent.)  and  then  with 
iodine  solution  (1-351  per  cent.).  One  c.c.  of 
the  iodine  solution  corresponds  with  o-oi  grm. 
of  antipyrin  (volumetric  method). 

BOUSSINGAULT  (nitric  acid). — A  little  hydrochloric 
acid  is  boiled  in  a  test-tube,  and  a  few  drops  of 
a  dilute  sulphuric  acid  solution  of  indigo,  and 
then  the  solution  under  examination  are  added. 
In  the  presence  of  nitric  acid  the  indigo  is 
bleached. 

BRAND  (quinine  and  quinidine). — On  mixing  these 
alkaloids  with  chlorine  water  a  brilliant  emerald- 
green  coloration  is  produced  (thalleioquin  reac- 
tion). Cinchonine  and  cinchonidine  do  not  give 
this  reaction. 

BRAND  (abrastol  in  wine). — After  removal  of  the 

colouring  matter  of  the  wine  by  means  of  lead 

dioxide  and  sulphuric  acid  the  wine  is  extracted 

with   chloroform,   and  the  extract  evaporated. 

68 


REAGENTS   AND   REACTIONS. 

Abrastol  may  be  detected  in  the  residue  by  the 
green  coloration  which  it  gives  with  sulphuric 
acid. 

BRANDES  (creosote). — On  treating  i  c.c.  of  creosote 
with  10  c.c.  of  20  per  cent,  alcoholic  potassium 
hydroxide  solution  a  compact  crystalline  mass  is 
obtained. 

BRAUN  (nitric  acid}. — On  adding  to  the  solution 
of  a  nitrate  a  little  aniline  sulphate  and  then 
strong  sulphuric  acid  a  bluish-violet  coloration  is 
obtained. 

BRAUN  (dextrose). — A  red  coloration  is  produced 
when  a  solution  of  dextrose  is  heated  with  a  few 
drops  of  a  solution  of  picric  acid  (i  :  250). 

BRAUTIGAM-EDELMANN  (horseflesh) . — The  broth 
prepared  from  the  flesh  is  freed  from  proteins 
and  tested  with  a  potassium  solution  of  iodine. 
In  the  presence  of  horseflesh,  which  contains 
glycogen,  a  Bordeaux-red  coloration  is  produced. 

BREMER  (dextrose  in  blood). — Equal  volumes  of  a 
saturated  solution  of  eosin  and  of  methylene 
blue  are  mixed,  and  the  resulting  precipitate 
washed,  dried,  and  powdered.  To  this  powder 
is  added  an  additional  one  twenty-fourth  of 
eosin  and  one  fourth  of  methylene  blue.  A  glass 
coated  with  the  preparation  of  the  blood  is 
immersed  in  a  solution  of  0-05  grm.  of  this 
powder  in  10  c.c.  of  35  per  cent,  alcohol.  The 
presence  of  dextrose  is  indicated  by  a  blue-black 
coloration. 

BREMER  (sesame  oil  in  margarine}. — Ten  drops  of 
furfural  are  added  to  a  cold  mixture  of  50  c.c.  of 
strong  sulphuric  acid  and  50  c.c.  of  alcohol.  A 
drop  of  this  reagent  brought  in  contract  with 
margarine  containing  sesame  oil  produces,  after 
a  few  minutes,  a  cherry-red  coloration. 

BRISSEMORET-DERRIEN  (digitalis  glucosides) . — A 
solution  of  the  glucosides  in  30  c.c.  of  a  4  per 
cent,  solution  of  oxalic  acid,  previously  treated 


REAGENTS  AND   REACTIONS. 

with  sodium  amalgam,  when  poured  on  to 
strong  sulphuric  acid  and  allowed  to  stand,  gives 
a  green  coloration  in  the  presence  of  digitoxine, 
and  a  cherry-red  zone  in  the  presence  of  amor- 
phous digitaline. 

BROUARDEL-BOUTMY  (ptomaines  and  vegetable 
alkaloids). — Ptomaines,  when  treated  with  a 
mixture  of  potassium  ferricyanide  and  ferric 
chloride,  give  Prussian  blue.  This  reaction, 
however,  does  not  always  take  place. 

BRUCKE  (proteins}. — Coagulated  albumin  gives  a 
violet  coloration  when  suddenly  treated  with  a 
dilute  solution  of  copper  sulphate,  and  then, 
after  removal  of  the  excess  of  liquid,  with  dilute 
sodium  hydroxide  solution  (biuret  reaction). 

BRUCKE  (dextrose}. — The  reagent  is  prepared  by 
boiling  5 '5  grms.  of  recently-precipitated  basic 
bismuth  nitrate  in  a  solution  of  30  grms.  of 
potassium  iodide  in  150  c.c.  of  water,  and  adding, 
after  five  minutes,  5  grms.  of  25  per  cent, 
hydrochloric  acid.  In  the  presence  of  dextrose 
this  reagent  gives  a  black  coloration. 

BRULLE  (olive  oil). — Ten  c.c.  of  the  oil  are  boiled 
with  o-i  grm.  of  powdered  albumin  and  25  c.c. 
of  nitric  acid.  After  the  albumin  has  dissolved 
the  oil  (if  pure  olive  oil)  becomes  practically 
colourless,  and  when  cold  is  pale  yellow  and 
turbid,  and,  after  twenty-four  hours,  solidifies 
to  a  solid  yellow  mass.  The  presence  of  cotton- 
seed oil  causes  the  initial  yellow  coloration  to 
continue  to  orange  and  brownish-red,  whilst, 
as  a  rule,  solidification  does  not  take  place. 

BRUNNER  (alkaloids). — The  reagents  suggested 
by  Brunner  for  the  identification  of  alkaloids 
include  the  following  : — 

(i)  The  alkaloid  is  carefully  heated  with  a 

crystal   of   chloral   hydrate    and    15    drops    of 

sulphuric  acid.    Morphine,  codeine,  and  apomor- 

phine  give  a  grass-green  coloration  ;    narcotine, 

70 


REAGENTS  AND   REACTIONS. 

first  a  green  and  then  a  brown  and  red  coloration ; 
papaverine,  violet,  changing  to  rose  colour  when 
heated ;  colchicine,  veratrine,  and  picrotoxine,  a 
red  coloration.  Bromal  hydrate  under  the  same 
conditions  gives  analogous  colorations  with 
morphine,  narcotine,  narceine,  and  papaverine. 

(2)  On    adding    to   the   alkaloid   a   drop    of 
paraldehyde   and   5    drops   of   sulphuric   acid, 
morphine  and  codeine  give  an  orange  coloration ; 
apormorphine,  a  violet  coloration ;  papaverine, 
reddish-yellow  and  then  red;  solanine  orange; 
and  picrotoxine,  a  yellow  coloration  changing 
to  red  on  heating. 

(3)  When  the  alkaloid  is  treated  with  4  to 
5    drops    of    a    recently-prepared    solution    of 
2  drops  of  furfural  in  10  c.c.  of  strong  sulphuric 
acid  the  following  colorations  are  produced : — 
Morphine,  bright  red,  changing  on  heating  to 
olive  green  ;    codeine  and  apomorphine,  red ; 
narcotine  and  narceine,  as  with  chloral  hydrate  ; 
papaverine,     violet     on     heating ;      solanine, 
yellowish-brown ;     veratrine,   first   yellow   and 
then  green ;    picrotoxine,  first  yellow  and  then 
reddish-brown. 

(4)  The  alkaloid  is  treated  with  4  to  5  drops 
of  a  solution  of   i   grm.   of  orthonitrophenyl- 
propiolic  acid  in  100  c.c.  of  sulphuric  acid,  and 
the  following  colorations  are  obtained  : — Mor- 
phine,   codeine    and    apomorphine,    violet    on 
heating  ;  papaverine,  violet  in  the  cold,  reddish 
on  heating  ;    solanine,  yellow  ;   picrotoxine,  red 
and  then  olive-green.     Narcotine  and  narceine 
give  the  same  colour  reactions  as  with  chloral 
hydrate. 

BRUYLANTS    (morphine). — (i)    On    adding   a   few 

drops  of  an  aqueous  solution  of  iodic  acid  to  a 

sulphuric  acid  solution  61  morphine,  previously 

heated,  a  lilac  or  rose  coloration  is  produced. 

(2)  When  a  drop  of  a  solution  of  morphine  in 


REAGENTS  AND  REACTIONS. 

strong  sulphuric  acid  is  heated  on  a  porcelain 
tile  and  treated  with  a  drop  of  Frohde's  reagent 
a  green  coloration  is  produced. 

BUCKINGHAM  (alkaloids}. — The  reagent  consists  of 
a  recently-prepared  solution  of  i  grm.  of 
ammonium  molybdate  in  16  grms.  of  sulphuric 
acid,  which  has  been  heated  until  the  liquid  is 
clear.  This  reagent  gives  precipitates  of  various 
colours  with  many  alkaloids. 

BUYWID  (nitrous  acid}. — From  70  to  80  c.c.  of 
the  liquid  under  examination  are  heated  with  a 
few  drops  of  hydrochloric  acid,  and  a  few  drops 
of  a  o-oi  to  0-02  per  cent,  alcoholic  solution  of 
indol  are  added.  In  the  presence  of  nitrites 
there  appears,  after  a  few  minutes,  a  red  colora- 
tion, which  augments  in  intensity. 


C. 

CAILLETET  (tartaric  acid  in  citric  acid}. — A  crystal 
of  citric  acid  is  treated  with  a  saturated  solu- 
tion of  potassium  bichromate.  Pure  citric  acid 
slowly  forms  a  brown  zone,  but  if  tartaric  acid  is 
present  a  dark  violet  coloration  is  obtained. 

CAILLETET  (oils). — The  reagent  consists  of  a 
mixture  of  12  parts  of  phosphoric  acid  (sp. 
gr.  1-84)  with  10  parts  of  nitric  acid  (sp.  gr.  1-37). 
The  oils  are  shaken  with  this  mixture,  and  from 
their  changes  in  colour  and  consistence  con- 
clusions are  drawn  as  to  their  purity.  Olive 
oil  gives  a  bluish-green  coloration,  and  the 
presence  of  other  oils  affects  this  coloration. 

CAILLETET  (copper  in  oils). — Ten  c.c.  of  the  oil 
are  shaken  with  5  c.c.  of  a  2  per  cent,  ethereal 
solution  of  pyrogallic  acid.  In  the  presence  of 
copper  the  mixture  assumes  a  brown  colour, 
owing  to  the  separation  of  copper  pyrogallate. 

CAMOIN  (sesamd  oil} — A  red  coloration  is  obtained 
.72 


REAGENTS  AND  REACTIONS. 

on  shaking  two  volumes  of  the  oil  with  one 
volume  of  hydrochloric  acid  containing  2  per 
cent,  of  sugar  (cf.  BAUDOUIN,  VILLAVECCHIA 
and  FABRIS). 

CAMPANI  (dextrose  in  urine]. — The  reagent  consists 
of  a  concentrated  solution  of  lead  acetate  mixed 
with  a  dilute  solution  of  copper  acetate.  This 
solution  is  reduced  by  dextrose,  but  not  by  cane 
sugar. 

CAMPBELL-STARCH  (tartaric  acid  in  citric  acid}. — 
One  c.c.  of  a  10  per  cent,  solution  of  ammonium 
molybdate  is  added  to  i  grm.  of  the  citric  acid 
under  examination.  If  a  blue  coloration  appears 
the  liquid  is  heated  until  it  disappears.  When 
cold,  5  c.c.  of  a  25  per  cent,  solution  of  hydro- 
gen peroxide  are  added,  and  an  intense  yellow 
coloration  should  then  be  obtained. 

CAPRANICA  (guanine}. — A  hot  solution  of  guanine 
hydrochloride  gives  a  yellow  precipitate  when 
treated  with  a  saturated  solution  of  picric  acid  ; 
with  potassium  chromate  in  concentrated  solu- 
tion a  crystalline  reddish  orange  precipitate ; 
and  with  potassium  ferrocyanide  solution  a 
brownish-yellow  precipitate. 

CAPRANICA  (biliary  pigments). — The  urine  under 
examination  is  treated  with  a  little  bromine 
water,  and  the  mixture  shaken  with  alcohol 
and  ether  (i  :  i).  In  the  presence  of  biliary 
pigments  there  is  obtained  a  green  coloration 
changing  to  indigo-blue,  then  to  violet,  and 
finally  to  yellowish-red.  On  adding  hydro- 
chloric acid  and  shaking  the  mixture,  the  acid 
layer  becomes  coloured  as  described. 

CAREY-LEA  (hydrocyanic  acid). — The  reagent  con- 
sists of  a  solution  of  i  grm.  of  ferrous  ammonium 
sulphate  and  i  grm.  of  uranium  nitrate  in 
250  c.c.  of  water.  In  the  presence  of  hydro- 
cyanic acid  or  its  salts  an  intense  reddish- 
purple  coloration  and  precipitate  is  obtained 
73 


REAGENTS  AND   REACTIONS. 

CARNOT  (potassium  salts). — On  treating  i  drop  of 
a  N/2  solution  of  bismuth  nitrate  with  2  to  3 
drops  of  a  N/2  solution  of  sodium  thiosulphate, 
then  with  10  to  15  c.c.  of  absolute  alcohol,  and 
finally  adding  a  small  quantity  of  a  potassium 
salt,  a  yellow  precipitate  of  bismuth  potassium 
thiosulphate  is  obtained. 

CARO  (per sulphates). — When  a  solution  of  a  per- 
sulphate is  added  to  a  neutral  2  per  cent, 
solution  of  aniline,  and  the  liquid  is  heated  for  a 
few  minutes,  a  brownish-orange  precipitate  is 
immediately  obtained.  In  very  dilute  solutions, 
however,  only  a  brown  coloration  appears. 
When  the  precipitate  is  treated  with  hot  benzene 
a  product  is  obtained  which  dissolves  in  hydro- 
chloric acid,  forming  a  yellow  solution,  changing 
to  violet  on  heating. 

CARO  (alkaloids). — The  reagent  consists  of  strong 
sulphuric  acid  and  ammonium  persulphate. 
It  gives  an  orange  coloration  with  brucine, 
blood-red  with  thebaine,  red-brown  with  nar- 
cotine,  and  yellow  with  quinine. 
CARO-FISCHER  (hydrogen  sulphide). — The  solution 
is  treated  with  one-fiftieth  of  its  volume  of 
strong  hydrochloric  acid,  a  crystal  of  ^-amino- 
dimethylaniline  sulphate  dissolved  in  the  liquid, 
and  2  drops  of  ferric  chloride  solution  then 
added.  In  the  presence  of  hydrogen  sulphide  a 
blue  coloration  (methylene  blue)  is  obtained. 
CARO-FISCHER  (cobalt). — On  mixing  equal  volumes 
of  a  concentrated  solution  of  sodium  bicarbonate 
and  hydrogen  peroxide  a  green  coloration  is 
immediately  obtained  in  the  presence  of  a  trace 
of  cobalt. 

CARO-FISCHER  (chromates,  bichromates).  --  On 
shaking  hydrogen  peroxide  and  ether  with  a 
very  dilute  solution  of  a  chromate  or  bichromate, 
in  the  presence  of  sulphuric  acid,  the  ether  is 
coloured  bright  blue. 

74 


REAGENTS  AND   REACTIONS. 

CARPENE  (tannins  in  wine). — A  saturated  solution 
of  zinc  acetate  in  5  per  cent,  ammonia  solution 
gives  a  precipitate  in  liquids  containing  tannin, 
but  does  not  precipitate  gallic  acid. 

CARREZ  (antipyriri). — The  substance  under  ex- 
amination (o-oi  grm.)  is  mixed  with  o-oi  grm. 
of  quinine  sulphate,  and  dissolved  in  25  c.c.  of 
90  per  cent,  alcohol.  One  c.c.  of  this  solution 
is  evaporated  to  dryness  in  a  crucible,  and  a 
few  drops  of  0-3  per  cent,  bromine  water,  followed 
by  a  few  drops  of  ammonia  solution,  are  made 
to  fall  on  to  the  residue.  The  appearance  of  a 
red-violet  coloration  indicates  the  presence  of 
antipyrin.  Sensitiveness  =  o-i  mgrm. 

CARREZ  (albumin  in  urine). — One  grm.  of  resorcinol 
is  dissolved  in  2  c.c.  of  water,  and  a  few  c.c.  of 
the  urine  are  added  to  the  solution,  so  as  not  to 
mix  the  two  liquids.  At  the  zone  of  contact  a 
white  ring  is  formed.  Urates,  urea,  and  alkaloids 
do  not  give  this  reaction,  whilst  peptone  forms 
a  ring  which  disappears  on  heating. 

CAZENEUVE  (coal-tar  dyes  in  wine}. — Pure  wine, 
when  shaken  with  yellow  mercuric  oxide,  yields 
a  colourless  filtrate,  whilst  a  coloured  nitrate 
indicates  the  presence  of  coal-tar  dyestuffs. 

CENCI  (salicylic  acid}. — On  adding  a  few  drops  of 
a  solution  of  5  grms  of  zinc  in  30  c.c.  of  nitric 
acid  to  a  hot  solution  containing  salicylic 
acid  or  a  salicylate  there  is  produced  a  violet 
coloration,  which  on  boiling  changes  to  bright 
red.  Sensitiveness  =  i  :  60,000. 

CHAPMAN  (eugenol  .and  isoeugenol). — One  c.c.  of 
eugenol  or  isoeugenol  is  dissolved  in  5  c.c.  of 
acetic  anhydride  and  the  solution  treated  with 
a  drop  of  sulphuric  acid  and  a  fragment  of  pure 
zinc.  In  the  presence  of  eugenol  the  addition 
of  sulphuric  acid  causes  a  purple-red  or  claret-red 
coloration  to  appear,  and  zinc  chloride  gives  a 
pale  yellow  coloration  to  the  mixture.  Iso- 
75 


REAGENTS  AND   REACTIONS. 

eugenol,  however,  gives  a  rose  coloration, 
changing  to  light  brown  with  sulphuric  acid, 
whilst  zinc  chloride  produces  a  red  coloration. 

CHAPMAN  (safrol  and  isosafrol). — A  solution  of 
i  c.c.  of  safrol  in  5  c.c.  of  acetic  anyhdride  gives, 
when  treated  with  a  drop  of  strong  sulphuric 
acid,  an  emerald-green  coloration,  changing  to 
brown,  whilst  with  zinc  chloride  the  mixture  is 
coloured  first  pale  blue  and  then  light  brown. 
Isosafrol  under  the  same  conditions  gives  with 
strong  sulphuric  acid  a  rose  coloration,  changing 
to  red  ;  with  zinc  chloride  it  immediately  gives  a 
rose  coloration,  changing  to  brown. 

CHAPMAN-SMITH  (tartaric  acid  in  citric  acid). — A 
strongly  alkaline  boiling  solution  of  perman- 
ganate gives  a  green  coloration  with  citric  acid, 
whilst,  in  the  presence  of  tartaric  acid,  it  is 
decomposed,  with  the  separation  of  manganese 
dioxide. 

CHASTAING-RABILLOT  (morphine). — The  substance 
under  examination  is  mixed  with  0-5  grm.  of 
oxalic  acid,  and  then  with  i  c.c.  of  sulphuric  acid; 
and  heated  for  an  hour  in  an  oil-bath  at  120°  to 
125°  C.  After  cooling,  3  to  4  c.c.  of  water  are 
added,  and  sufficient  alcoholic  sodium  hydroxide 
solution  (4  to  5  c.c.  of  36°)  to  render  the  liquid 
strongly  alkaline.  The  mixture  is  left  for  twelve 
hours  exposed  to  the  air  or  to  an  atmosphere  of 
oxygen.  It  is  then  acidified  with  20  per  cent, 
hydrochloric  acid,  and  under  such  conditions  the 
mixture,  in  the  presence  of  morphine,  soon 
assumes  a  blue  or  bluish-green  colour.  The 
liquid  is  extracted  with  chloroform,  which 
becomes  of  a  blue  colour,  and  on  spontaneous 
evaporation  deposits  blue  crystals  of  morphine. 

CHAUTARD  (acetone  in  urine}. — The  reagent  con- 
sists of  a  solution  of  magenta  in  sulphurous  acid  ; 
when    added    to    urine    containing    acetone    it 
produces  a  violet  coloration. 
76 


REAGENTS  AND   R 

CHRISTEL  (picric  acid). — (i)  On  adding  ammoniacal 
lead  acetate  solution  to  an  aqueous  solution  of 
picric  acid  a  rose-coloured  precipitate  is  obtained, 
whilst  copper  sulphate  forms  a  green  pre- 
cipitate. 

(2)  An  aqueous  solution  of  methyl  green  gives 
with    picric    acid    a    green    precipitate,    which 
dissolves  in  a  large  volume  of  water  to  form  a 
green  solution. 

(3)  An  alkaline  solution  of  stannous  chloride, 
as  also  ammonium  sulphide,  gives  a  red  colora- 
tion with  picric  acid. 

(4)  When  picric  acid  is  treated  with  zinc  and 
dilute    sulphuric    acid    a    turbid    yellowish-red 
solution  is  obtained.     On  mixing  this  solution 
with  a  large  amount  of  alcohol,  and  filtering 
the  mixture,  after  a  short  time  there  is  produced 
a  green  coloration,  changing  to  violet  and  then 
to  reddish- violet. 

CHRISTENSEN  (albumin  in  urine). — A  dilute  solu- 
tion of  tannin  gives  a  precipitate  when  added  to 
a  solution  containing  albumin. 

CIAMICIAN-MAGNANINI  (scatol). — A  reddish-purple 
coloration  is  obtained  on  heating  scatol  with 
sulphuric  acid. 

CLARUS  (solanine). — Solanine  gives  a  bright  blue 
coloration  when  treated  with  a  solution  of 
chromic  acid. 

COHEN  (albumin). — Albumin  gives  a  turbidity  or 
precipitate  when  treated  with  a  50  per  cent, 
acetic  acid  solution  of  i  grm.  of  iodine  and 
i  grm.  of  potassium  iodide. 

COHN-MEHRING  (hydrochloric  acid  in  gastric  juice). — - 
On  adding  cinchonine  to  gastric  juice  cinchonine 
hydrochloride  is  formed,  and  may  be  quanti- 
tatively estimated. 

COLASANTI  (thiocyanic  acid  in  saliva). — The  saliva 
is  treated  with  alcohol  and  filtered,  the  filtrate 
evaporated  on  the  water-bath,  the  residue 
77 


REAGENTS  AND   REACTIONS. 

dissolved  in  water,  and  the  solution  treated 
with  copper  sulphate.  Thiocyanic  acid  in 
saliva  gives  an  emerald-green  coloration. 

COLASANTI  (thiocyanates  and  essential  oil  of  mus- 
tard}.— A  very  dilute  solution  is  treated  with  a 
20  per  cent,  solution  of  a-naphthol,  and  then, 
without  shaking,  with  twice  its  volume  of  strong 
sulphuric  acid.  In  the  presence  of  thiocyanates 
or  mustard  oil  an  emerald  green  ring  is  produced 
at  the  zone  of  contact.  On  shaking  the  mixture, 
the  liquid  assumes  a  violet  colour. 

CONRADY  (cane  sugar  in  lactose). — A  solution  of 
i  grm.  of  cane  sugar  in  10  c.c.  of  water  is  boiled 
for  five  minutes  with  o-i  grm.  of  resorcinol  and 
i  c.c.  of  hydrochloric  acid.  In  the  presence  of 
cane  sugar,  or  dextrose  andlaevulose,  the  mixture 
assumes  a  red  colour. 

CONROY  (cotton  oil  in  olive  oil). — A  mixture  of 
9  parts  of  oil  with  i  part  of  nitric  acid  (sp.  gr. 
1-40)  remains  fluid  when  cold,  and  assumes  a 
reddish-orange  colour  when  cotton  oil  is  present. 
Pure  olive  oil  under  the  same  conditions  forms  a 
solid  yellow  mass. 

CONTEJEAN  (free  hydrochloric  acid  in  gastric  juice). — 
When  freshly-precipitated  cobalt  carbonate  is 
dissolved  in  the  liquid  under  examination,  it 
gives  a  red  coloration,  changing  to  blue  on 
evaporation. 

CORNETTE  (resin  oils  in  vegetable  oils). — The  test 
is  based  upon  the  fact  that  sodium  resinates  are 
soluble  in  a  saturated  solution  of  sodium 
chloride,  whilst  the  sodium  salts  of  the  higher 
fatty  acids  are  insoluble  therein. 

COTTINI-FANTOGINI  (artificial  colours  in  wine). — 
Fifty  c.c.  of  the  wine  are  heated  with  6  c.c.  of 
strong  nitric  acid.  The  natural  colour  of  wine 
does  not  alter  after  an  hour,  whereas  wine  that 
has  been  artificially  coloured  is  decolorised 
within  five  minutes. 


REAGENTS  AND   REACTIONS. 

COTTON  (phenol). — An  aqueous  solution  of  phenol 
turns  yellow  when  treated  with  sulphuric  acid 
and  a  nitrate,  and  brown  when  treated  with 
ammonia,  and  on  the  subsequent  addition  of 
bromine  water  gives  a  green  coloration  which 
changes  to  intense  blue  on  heating. 

CRACE-CALVERT  (sesame  oil  in  olive  oil). — Olive 
oil  containing  sesame  oil  gives  a  greenish 
coloration  when  shaken  with  one-fifth  of  its 
volume  of  nitro-sulphuric  acid  (equal  parts  of 
sulphuric  acid  of  sp.  gr.  1-84,  and  nitric  acid  of 

sp.  gr.  1-33)- 

CRINON  (phenacetin). — Chlorine  water  or  a  solution 
of  calcium  hypochlorite  gives  a  reddish-violet 
coloration  with  phenacetin. 

CRIPP-DYMONT  (aloes). — A  mixture  of  0-05  grm. 
of  the  substance  with  15  drops  of  sulphuric 
acid  is  treated  with  4  drops  of  nitric  acid 
(sp.  gr.  1-42),  and  then  with  30  c.c.  of  water.  In 
the  presence  of  aloes  the  solution  gives  a  red- 
orange  coloration,  which  changes  to  carmine-red, 
and,  on  the  addition  of  ammonia,  to  blood-red. 

CRISMER  (tartar ic  acid  in  citric  acid). — The  acid  to 
be  tested  is  powdered,  and  heated  for  a  few 
minutes  on  the  water-bath  with  a  solution  of 
ammonium  molybdate  and  a  few  drops  of 
hydrogen  peroxide.  In  the  presence  of  tartaric 
acid  a  blue  coloration  is  obtained,  whilst  citric 
acid  gives  only  a  yellow  coloration.  Sensitive- 
ness =  i :  1,000. 

CRISMER  (aldehydes). — The  reagent  consists  of  a 
solution  of  potassium  iodide  and  mercuric 
chloride  which  has  been  treated  with  potassium 
hydroxide  or  baryta  water.  It  gives  a  coloured 
precipitate  with  aldehydes. 

CRISMER  (dextrose  in  urine). — The  reagent  is  pre- 
pared by  treating  o-i  grm.  of  safranine  in  100  cc. 
of  water  with  40  c.c.  of  potassium  hydroxide 
solution.  One  c.c.  of  the  urine  is  heated  with 
79 


REAGENTS  AND   REACTIONS. 

7  c.c.  of  the  reagent,  and  if  dextrose  be  present 
the  liquid  is  decolorised. 

CRISWELL  (dextrose  in  urine}. — The  reagent  con- 
sists of  35  grms.  of  copper  sulphate,  100  c.c.  of 
water,  200  grms.  of  glycerin,  and  450  c.c.  of 
20  per  cent,  sodium  hydroxide  solution.  It  is 
heated  for  fifteen  minutes,  and  then  cooled  and 
diluted  to  i  litre. 

CROKER  (stain  for  microscopy}. — A  solution  of 
i  grm.  of  powdered  cochineal,  18  grms.  of  alum, 
and  100  c.c.  of  water  is  evaporated  to  half  its 
volume,  filtered,  and  treated  with  0-5  c.c.  of 
liquid  phenol. 

CROLAS-DUCKER  (uranium  salts}. — Tincture  of 
cochineal  is  changed  to  green  when  treated  with 
alum  in  the  presence  of  uranium  salts. 

CROUZEL  (animal  fats  in  vaseline} . — A  solution  of 
potassium  permanganate  is  decomposed  by 
animal  and  vegetable  fats,  with  the  separation 
of  manganese  dioxide,  but  is  not  affected  by 
vaseline. 

CROUZEL  (santonine  in  urine}. — Urine  containing 
santonine  gives  a  carmine-red  coloration  when 
treated  with  freshly -prepared  lime  (e.g.,  from 
calcium  carbide). 

CRUMS  (manganese  salts}. — Manganese  salts,  when 
heated  with  lead  dioxide  and  i  c.c.  of  strong 
nitric  acid  and  then  diluted  with  water,  give  a 
solution  of  an  intense  violet  colour,  due  to  the 
formation  of  permanganic  acid.  Chlorides 
interfere  with  the  reaction. 

CUERBE  (narcotine}. — On  heating  a  solution  of 
narcotine  in  concentrated  sulphuric  acid,  which 
has  stood  for  one  or  two  hours,  with  a  little 
nitric  acid,  a  bright  red  coloration  is  obtained. 

CUNISSET  (biliary  pigments}. — Chloroform  assumes 
a  yellow  colour  when  shaken  with  urine  con- 
taining biliary  pigments. 

CURTMANN  (nitric  acid}. — A  solution  of  pyrogallic 
80 


REAGENTS  AND  REACTIONS. 

acid  in  sulphuric  acid  gives  a  yellow  coloration 
with  nitric  acid  in  the  proportion  of  as  little  as 
i  :  500,000. 

CURTMANN  (nitrous  acid). — Antipyrin  gives  a  green 
coloration  with  nitrous  acid. 

CURTMANN  (ammonia  and  hydrogen  sulphide). — On 
treating  a  solution  of  chloral  hydrate  with 
ammonia,  and  then  with  hydrogen  sulphide,  a 
reddish-brown  coloration  or  precipitate  is 
obtained.  Conversely,  a  solution  of  chloral 
hydrate  containing  hydrogen  sulphide  is  coloured 
yellow  on  the  addition  of  a  little  ammonia. 

CUTOLA  (cellulose). — Cellulose  is  coloured  blue 
by  a  50  per  cent,  solution  of  hydriodic  acid 
containing  iodine. 

CZAPLEWSKI  (stain  for  bacteriology). — One  grm.  of 
magenta  is  ground  up  with  5  c.c.  of  liquid 
phenol,  and  then  mixed  with  50  c.c.  of  glycerin 
and  100  c.c.  of  water.  For  use  as  a  stain,  the 
liquid  is  diluted  with  4  to  5  volumes  of  water. 

CZERNIEWSKI  (aspidospermin) .  —  Aspidospermin, 
when  heated  with  dilute  sulphuric  acid  and  a  trace 
of  potassium  chlorate,  gives  a  red  coloration, 
which  after  a  short  time  becomes  permanent. 

CZOKOR  (stain  for  microscopy). — A  solution  of 
phenol  is  treated  with  i  grm.  of  carmine  and 
alum  in  100  c.c.  of  water. 

CZUMPELITZ  (alkaloids). — The  reagent  consists  of 
a  solution  of  fused  zinc  chloride  in  30  c.c.  of 
strong  hydrochloric  acid  and  water.  On 
evaporating  the  substance  under  examination 
on  the  water-bath,  with  a  few  drops  of  the 
reagent,  distinctive  colorations  are  given  by  the 
various  alkaloids. 

D. 

DACCOMO  (filicic  acid). — A  solution  of  filicic  acid 
in  ether  gives,  when  shaken  with  an  aqueous 
R.R.  81 


4ARMACY 


REAGENTS  AND   REACTIONS. 

solution  of  copper  acetate,  a  flocculent  bright 
green  precipitate  of  the  copper  salt. 

DACLIN  (pure  water  of  bitter  almonds). — The 
sample  is  distilled  and  the  distillate  treated  with 
cocaine,  which  gives  a  crystalline  precipitate 
of  cocaine  hydrocyanide.  Artificial  almond- 
water  does  not  show  this  reaction. 

DACLIN  (santonine  in  urine). — Ten  c.c.  of  the 
urine  are  shaken  with  5  c.c.  of  chlorofrom,  the 
mixture  left  to  separate,  and  the  chloroform 
layer  decanted,  and  evaporated  at  a  gentle 
heat.  The  residue  is  divided  into  two  portions. 
One  of  these  is  gradually  heated  with  i  to  2 
drops  of  pure  sulphuric  acid,  and,  in  the  presence 
of  santonine,  a  violet  coloration  immediately 
appears.  The  other  portion  is  treated  with 
2  drops  of  an  alcoholic  solution  of  potassium 
hydroxide,  which  causes  a  bright  rose  coloration 
to  appear. 

DAHLMANN  (lignin  in  paper). — A  o-i  per  cent, 
solution  of  sodium  aurochloride  gives  a  yellow 
coloration  with  lignin,  and  a  red-brown  coloration 
with  sulphite  cellulose  and  soda  cellulose,  whilst 
the  cellulose  of  cotton  remains  unaltered. 

DAHNON  (arbutin). — When  arbutin  is  moistened 
with  strong  nitric  acid,  then  heated  with  a 
mixture  of  i  volume  of  sulphuric  acid  with 
8  volumes  of  alcohol,  and  subsequently  treated 
with  an  excess  of  potassium  carbonate  solution, 
it  gives  violet  coloration. 

DAVID  (gallic  and  gallotannic  acids). — On  treating 
a  solution  of  gallotannic  acid  with  a  solution  of 
barium  chloride  and  potassium  hydroxide  a  red 
precipitate  is  obtained,  the  intensity  of  the 
colour  of  which  gradually  increases.  Gallic  acid, 
under  the  same  conditions,  gives  a  blue  pre- 
cipitate. 

DAVY  (alkaloids). — The  reagent  consists  of  a 
10  per  cent,  solution  of  sodium  nitroprusside  ; 
82 


REAGENTS   AND   REACTIONS. 

it  forms  microcrystalline  precipitates  with 
various  alkaloids. 

DAVY  (phenol). — On  adding  sulphomolybdic  acid 
to  a  solution  containing  phenol  a  yellow  colora- 
tion, changing  to  yellowish-brown,  is  immediately 
obtained.  Afterwards  the  colour  changes  to 
red-brown,  and  finally  to  reddish-purple.  If  the 
phenol  solution  is  diluted  it  does  not  give  the 
reddish-purple  coloration,  but  an  olive-green 
coloration,  which  changes  rapidly  to  blue. 

DAY  (pus  in  urine). — The  reaction  consists  in 
adding  i  or  2  drops  of  oxidised  guaiacum  tincture 
to  the  urine  ;  in  the  presence  of  pus  a  blue 
coloration  is  produced. 

DEBRUN  (coal-tar  colours  in  wine}. — Ten  c.c.  of  the 
wine  are  heated  for  one  minute  with  o-i  grm. 
of  a  mixture  of  i  part  of  zinc  oxide  and  2  parts 
of  mercuric  acetate.  Genuine  wine  is  decolorised, 
whereas  wine  containing  coal-tar  colours  remains 
persistently  red. 

DEEN  (VAN)  (blood}. — A  dilute  solution  of  blood 
gives  a  blue  coloration  when  treated  with  a  few 
drops  of  guaiacum  tincture  and  of  ozonised  oil  of 
turpentine. 

DEGENER  (dextrose  in  urine}. — The  reagent  is  a 
modification  of  Fehling's  solution. 

DEISS  (cotton  oil  in  olive  oil). — Ten  c.c.  of  the  oil 
are  dissolved  in  100  c.c.  of  ether,  and  the  solution 
is  shaken  with  5  c.c.  of  a  saturated  solution  of 
lead  acetate.  On  shaking  the  mixture  with 
5  c.c.  of  ammonia  solution,  a  more  or  less  pro- 
nounced yellowish-red  coloration  is  obtained  in 
the  presence  of  cotton  oil. 

DELAFIELD  (stain  for  microscopy}. — To  100  c.c.  of 
a  saturated  solution  of  ammonium  alum  are 
added  4  grms.  of  haematoxylin  dissolved  in 
25  c.c.  of  absolute  alcohol,  and  the  solution  is 
exposed  to  the  light  for  three  or  four  days  in  an 
open  bottle.  The  liquid  is  then  filtered,  and  the 
83  6-2 


REAGENTS  AND   REACTIONS. 

filtrate  mixed  with  100  c.c.  of  glycerin  and 
100  c.c.  of  methyl  alcohol,  and  exposed  to  the 
light  until  the  colour  no  longer  changes.  It  is 
then  filtered  again  and  kept  in  closed  bottles. 

DELF  (alkaloids). — (i)  A  solution  of  mercuric 
iodide  in  potassium  iodide  (see  MAYER).  (2) 
Potassium  platinocyanide. 

DELF-SCHWARZENBACH  (alkaloids). — The  reagent 
consists  of  nitric  acid  and  ammonia.  Charac- 
teristic colorations  are  obtained  with  certain 
alkaloids. 

DEMSKI-MORAWSKI  (resin  oils  in  mineral  oils). — 
The  test  is  based  upon  the  solubility  of  oils  in 
acetone,  and  on  the  different  behaviour  of  the 
solutions  towards  polarised  light. 

DENIGES  (acetone). — The  reagent  consists  of  a 
solution  of  5  grms.  of  mercuric  oxide  in  20  c.c.  of 
strong  sulphuric  acid  and  100  c.c.  of  water.  It 
is  heated  on  the  water-bath  with  an  equal 
volume  of  the  solution  under  examination  ;  in 
the  presence  of  acetone  a  turbidity  or  white 
precipitate  is  obtained. 

DENIGES  (aceto-acetic  acid). — A  liquid  containing 
aceto-acetic  acid  gives  a  bright  red  coloration  on 
the  addition  of  sodium  nitroprusside. 

DENIGES  (citric  acid). — Five  grms.  of  mercuric 
oxide  are  dissolved  in  a  mixture  of  100  c.c.  of 
water  and  20  c.c.  of  strong  sulphuric  acid.  If 
a  solution  containing  citric  acid  be  heated  to 
boiling  with  one-twentieth  of  its  volume  of  the 
reagent,  and  from  3  to  4  drops  of  N/io  potassium 
permanganate  solution  added,  a  white  crystalline 
precipitate  will  be  obtained.  Sensitiveness  = 
i  :  2,000. 

DENIGES  (nitrous  and  nitric  acids). — The  reagent 
consists  of  an  aqueous  5  per  cent,  solution  of 
antipyrin.  When  i  c.c.  of  the  solution  under 
examination  is  heated  with  3  to  4  drops  of 
sulphuric  acid  and  10  drops  of  the  reagent  are 
84 


REAGENTS  AND   REACTIONS. 

added,  after  cooling,  a  greenish-blue  to  greenish- 
yellow  coloration  is  obtained  in  the  presence  of 
nitrous  acid.  On  adding  to  this  mixture  an 
additional  3  c.c.  of  sulphuric  acid,  a  reddish- 
orange  coloration  is  obtained  in  the  presence  of 
nitric  acid,  and  on  dilution  with  water  the  colour 
is  changed  to  carmine-red. 

DENIGES  (tartaric  acid). — The  reagent  consists  of 
a  solution  of  2  grms.  of  resorcinal  and  0-5  c.c.  of 
sulphuric  acid  in  100  c.c.  of  water.  The  substance 
under  examination  is  heated  to  125°  C.  with 
i  c.c.  of  the  reagent ;  and  if  tartaric  acid  be 
present  the  solution  is  coloured  red.  Any 
oxidising  substances  present  should  be  reduced 
by  means  of  zinc  and  hydrochloric  acid. 

DENIGES  (uric  acid). — On  evaporating  a  trace  of 
uric  acid  with  bromine  water  to  dryness,  and 
treating  the  residue  with  a  little  strong  sulphuric 
acid  and  a  few  drops  of  benzene  containing 
thiophen,  a  bright  blue  coloration  is  produced. 

DENIGES  (methyl  alcohol  in  ethyl  alcohol). — To 
0*1  c.c.  of  the  alcohol  are  added  1-5  c.c.  of  a 
i  per  cent,  solution  of  potassium  permanganate 
and  0-2  c.c.  of  sulphuric  acid.  After  three 
minutes,  the  excess  of  permanganate  is  decom- 
posed by  the  addition  of  oxalic  acid  (i  c.c.  of  a 
saturated  solution)  and,  subsequently,  of  sul- 
phuric acid.  The  colourless  liquid  is  then 
treated  with  5  c.c.  of  magenta  bleached  with 
sulphurous  acid  (see  SCHIFF).  In  the  presence 
of  even  a  trace  of  methyl  alcohol,  a  violet 
coloration  is  produced  within  fifteen  minutes. 

DENIGES  (anilides). — All  anilides  give  a  yellowish- 
red  precipitate  when  heated  with  an  alcoholic 
solution  of  sodium  hypobromite. 

DENIGES  (bromine). — The  reagent  is  prepared  by 

heating  to  boiling  5  c.c.  of  a  i  per  cent,  aqueous 

solution  of  strychnine  sulphate  with  5  c.c.  of 

pure  hydrochloric  acid  and  4  to  5  grms.  of  pure 

85 


REAGENTS  AND   REACTIONS. 

granulated  zinc,  allowing  the  mixture  to  stand 
for  five  to  ten  minutes  at  the  ordinary  tempera- 
ture, and  then  cooling  it  in  water,  and  decanting 
the  supernatant  liquid.  On  shaking  i  c.c.  of  the 
reagent  with  5  c.c.  of  a  solution  containing  not 
more  than  i  grm.  of  free  bromine  per  litre,  a 
purple  coloration  is  obtained.  When  sufficiently 
diluted  the  solution  shows  absorption  bands  in 
the  yellow  part  of  the  spectrum.  In  more  con- 
centrated solution  the  dark  band  extends 
towards  the  blue,  but  not  towards  the  red  part 
of  the  spectrum.  Sensitiveness,  o-oi  mgrm. 
per  c.c. 

DENIGES  (chlorates}. — A  solution  of  2  grms.  of 
resorcinol  in  100  c.c.  of  water  containing  0*5  grm. 
of  sulphuric  acid  gives,  in  the  cold,  a  green 
coloration  with  chlorates. 

DENIGES  (distinction  between  arsenic  and  antimony 
deposits]. — Ten  grms.  of  ammonium  molybdate 
and  25  grms  of  ammonium  nitrate  are  dissolved 
in  100  c.c.  of  hot  water.  When  cold,  the  solution 
is  treated  with  100  c.c.  of  nitric  acid,  then  heated 
for  ten  minutes  on  the  water-bath,  allowed  to 
stand  for  forty-eight  hours,  and  filtered.  The 
solution  of  the  spots  in  nitric  acid  is  treated 
with  5  drops  of  this  reagent,  which,  in  the 
presence  of  o-ooi  mgrm.  of  arsenic,  gives  a  yellow 
precipitate  of  ammonium  arsenomolybdate. 

DENIGES  (benzoyl  group}. — A  small  quantity  of 
the  substance  is  heated  to  120°  C.  with  3  c.c. 
of  formaldehyde  in  sulphuric  acid  (2  c.c.  of 
40  per  cent,  formaldehyde  solution  in  100  c.c.  of 
sulphuric  acid).  A  red-brown  coloration  is 
obtained,  and  the  solution  shows  a  large  absorp- 
tion line  in  the  green  part  of  the  spectrum. 
Other  substances,  such  as  phenols,  opium 
bases,  etc.,  give  a  similar  coloration,  but 
usually  in  the  cold,  and,  in  any  case,  below 
100°  C. 

86 


REAGENTS   AND   REACTIONS. 

DENIGES  (mercaptans) . — The  reagent  consists  of 
a  i  per  cent,  solution  of  isatin  in  strong  sulphuric 
acid.  One  c.c.  of  strong  sulphuric  acid  is  mixed 
with  a  small  quantity  of  the  reagent,  and  on 
adding  to  the  mixture  an  alcoholic  solution  of 
mercaptan  a  bright  green  coloration  is  obtained. 
Aldehydes  and  higher  alcohols  interfere  with 
this  reaction.  Should  they  be  present,  the  solu- 
tion under  examination  is  treated  with  sodium 
hydroxide,  and  then  diluted  with  water,  and 
sodium  nitroprusside  is  added.  In  the  presence 
of  mercaptans  a  red  coloration  is  obtained. 

DENIGES  (copper). — A  solution  of  copper  gives  a 
red-violet  coloration  on  adding  an  excess  of 
potassium  bromide  and  sulphuric  acid. 

DENIGES  (ferrous  salts). — The  reagent  consists 
of  a  solution  of  alloxan.  It  gives  with  ferrous 
salts  a  blue  coloration  on  the  addition  of  sodium 
hydroxide.  This  reagent  also  gives  characteristic 
colorations  with  other  salts : — Zinc  and  cadmium, 
carmine- red  ;  magnesium,  violet ;  manganese, 
reddish-blue  ;  cobalt,  claret-red ;  and  nickel, 
yellowish-brown,  changing  to  deep  red. 

DENIGES  (manganese  salts). — A  dilute  solution 
containing  manganese  gives  a  black  precipitate 
with  sodium  hypobromite.  On  heating  the 
solution,  it  assumes  a  red  colour,  owing  to  the 
formation  of  potassium  permanganate. 

DENIGES  (stannous  salts). — The  reagent  is  prepared 
by  boiling  for  fifteen  minutes  a  solution  of  i  grm. 
of  brucine  in  10  c.c.  of  cold  nitric  acid  and 
500  c.c.  of  water.  Stannous  salts  impart  a 
reddish-violet  coloration  to  this  solution. 

DENIGES  (thiophen  in  benzene). — Five  grms.  of 
mercuric  oxide  are  dissolved  in  20  c.c.  of  strong 
sulphuric  acid  and  100  c.c.  of  water.  Ten  c.c. 
of  this  solution  are  mixed  with  30  c.c.  of  methyl 
alcohol  free  from  acetone,  and  10  c.c.  of  the 
mixture  are  treated  with  i  c.c.  of  the  benzene 


REAGENTS   AND   REACTIONS. 

under  examination.  In  the  presence  of  as  little 
as  o-ooi  per  cent,  of  thiophen  a  precipitate  or 
turbidity  is  obtained  after  a  few  seconds. 

DENIGES  (hydrogen  peroxide). — On  adding  to 
hydrogen  peroxide  i  c.c.  of  a  10  per  cent, 
aqueous  solution  of  ammonium  molybdale 
and  i  c.c.  of  sulphuric  acid,  an  intense  yellow 
coloration  is  produced. 

DENIGES  (tyrosin). — The  reagent  consists  of  a 
mixture  of  2  c.c.  of  sulphuric  acid  with  4  drops 
of  a  mixture  of  5  c.c.  of  aldehyde  with  10  c.c.  of 
90  per  cent,  alcohol.  On  adding  to  the  solution 
thus  obtained  a  trace  of  tyrosin,  the  mass  im- 
mediately assumes  a  red  colour. 

DESBASSIN  (nitric  acid). — This  is  the  well-known 
zone  reaction  with  sulphuric  acid  and  ferrous 
sulphate  (black  ring). 

DESESQUELLE  (phenols  in  urine). — Fifty  c.c.  of  the 
urine  are  shaken  with  2  c.c.  of  chloroform,  and 
the  chloroform  extract  separated,  and  gently 
heated  with  a  fragment  of  potassium  hydroxide. 
The  latter  becomes  coloured  in  a  characteristic 
way,  and  produces  a  flocculent  precipitate,  the 
colour  of  which  varies  with  the  nature  of  the 
phenol.  For  example,  /2-naphthol  gives  a 
greenish-blue  coloration. 

DEVOTO  (peptones  in  urine). — All  the  other 
proteins  are  precipitated  by  saturating  the  hot 
solution  with  crystallised  ammonium  sulphate, 
and  the  filtrate  is  tested  for  peptones  by  means 
of  the  biuret  reaction. 

DE-VRY  (quinine). — A  solution  of  quinoidine 
sulphate  (8  parts)  in  dilute  sulphuric  acid  (5  per 
cent.)  is  gradually  treated  with  a  potassium 
iodide  solution  of  iodine.  The  precipitate  is 
washed,  dried,  and  dissolved  in  six  times  its 
volume  of  92  to  94  per  cent,  alcohol,  the  solution 
filtered,  the  filtrate  evaporated,  and  the  residue 
dissolved  in  five  times  its  weight  of  alcohol.  This 


REAGENTS  AND   REACTIONS. 

solution  gives  with  solutions  of  quinine  a 
precipitate  of  quinine  iodosulphate. 
DIETERICH  (aloes  and  aloine). — (i)  On  evaporating 
an  extract  of  aloes  on  the  water-bath  with  a 
few  drops  of  nitric  acid  a  residue  is  obtained, 
which,  when  dissolved  in  alcohol,  forms  a  deep 
red  solution,  changing  to  pink  on  the  addition 
of  an  alcoholic  solution  of  potassium  cyanide. 

(2)  An  aqueous  solution  of  the  residue  gives, 
when   treated  with  gold   chloride,    colorations 
which  vary  with  the  nature  of  the  aloine.    The 
aloine   from   Cape   and   Socotra   aloes   gives   a 
raspberry-red  coloration  ;    barbaloine  gradually 
gives   a   violet   coloration ;    nataloine,   reddish 
violet ;   and  curacoa-aloine,  a  brick-red  colora- 
tion. 

(3)  On  adding  tannin  to  an  aqueous  solution 
of  the  residue  a  turbidity  is  produced  in  the 
presence  of  barbaloine.     The  aqueous  solution 
of  the  ordinary  residue  remains  clear,  on  the 
addition   of   potassium   bromide   solution   con- 
taining bromine,  in  the  case  of  nataloine,  but 
gives    a    turbidity    with    the    other    forms    of 
aloine. 

DIETERICH  (uric  acid). — A  solution  of  sodium 
hypochlorite  containing  bromine  gives  a  pink 
coloration  in  the  presence  of  uric  acid. 

DITTMAR  (alkaloids). — The  reagent  consists  of  a 
solution  of  iodine  chloride,  which  gives  yellow 
or  brown  precipitates  with  alkaloids. 

DI-VETERE  (castor  oil  in  olive  oil). — Five  c.c.  of 
hydrochloric  acid  (sp.  gr.  1-18)  are  shaken  in  a 
graduated  test-tube  with  10  c.c.  of  the  oil.  In 
the  presence  of  castor  oil  the  liquid  separates, 
on  standing,  into  three  layers,  the  uppermost 
consisting  of  olive  oil,  the  middle  of  castor  oil, 
and  the  bottom  of  acid.  The  depth  of  the  middle 
layer  will  afford  an  estimate  of  the  quantity  of 
castor  oil  present. 


REAGENTS  AND   REACTIONS. 

DOBBIN  (caustic  alkalies  in  carbonates). — A  solution 
of  i  grm.  of  potassium  iodide  in  50  c.c.  of  water 
is  treated  with  5  per  cent,  mercuric  chloride 
solution  until  a  persistent  precipitate  is  obtained. 
The  liquid  is  then  filtered,  and  0-3  grm.  of  ammo- 
nium chloride  is  dissolved  in  the  nitrate  and 
sodium  hydroxide  added  until  a  precipitate 
begins  to  form,  when  the  solution  is  filtered 
and  diluted  to  200  c.c.  The  reagent  gives  a 
yellow  coloration  with  traces  of  caustic  alkali  in 
alkali  carbonates. 

DODGE-OLCOTT  (Gurjun  balsam  in  Copaiba  balsam) . 
— On  treating  a  solution  of  4  drops  of  the  balsam 
in  15  c.c.  of  acetic  acid  with  6  drops  of  strong 
nitric  acid,  a  rose  coloration,  changing  to  reddish- 
purple,  is  obtained  in  the  presence  of  Gurjun 
balsam. 

DONATH  (chromic  acid). — Chromic  acid  liberates 
iodine  from  a  solution  of  potassium  iodide,  and 
this  iodine  will  dissolve  in  carbon  bisulphide, 
forming  a  violet  solution. 

DONATH  (cobalt). — A  concentrated  solution  of 
sodium  or  potassium  hydroxide  gives  an  intense 
blue  coloration  when  treated  with  a  few  drops 
of  a  solution  containing  cobalt.  On  heating  the 
liquid,  the  colour  becomes  brighter. 

DONATH  (tarry  substances  in  ammonia  solution). — 
The  ammonia  solution  acidified  with  sulphuric 
acid  decolorises  dilute  potassium  permanganate 
solution  when  tarry  substances  are  present. 

DONATH  (rosin  in  yellow  beeswax). — Five  grms.  of 
the  wax  are  heated  for  one  minute  with  20  to 
25  grms.  of  nitric  acid,  and  the  mixture  treated, 
first  with  20  c.c.  of  water,  and  then  with  ammonia 
solution  in  excess.  In  the  presence  of  rosin  the 
liquid  will  be  of  a  red-brown  colour,  whilst  pure 
wax  gives  a  yellow  solution. 

DONOGANY  (blood  in  urine). — Ten  c.c.  of  the  urine 
are  treated  with  i  c.c.  of  ammonium  sulphide 
90 


REAGENTS  AND   REACTIONS. 

and  i  c.c.  of  pyridine.  In  the  presence  of  blood, 
the  liquid  becomes  reddish-orange. 

DRAGENDORFF  (biliary  acids  in  urine). — The  urine 
is  acidified  with  sulphuric  acid  and  shaken,  first 
with  petroleum  spirit  to  remove  colouring 
matters,  and  then  with  amyl  alcohol  to  extract 
biliary  pigments.  After  neutralisation  with 
ammonia,  the  liquid  is  evaporated  to  dryness, 
and  the  residue  taken  up  with  a  little  water. 
The  aqueous  solution,  when  treated  with  a 
fragment  of  sugar  and  added  to  sulphuric  acid 
so  as  to  form  an  upper  layer,  gives  a  charac- 
teristic red  coloration. 

DRAGENDORFF  (alkaloids). — Five  grms.  of  bismuth 
iodide  are  dissolved  in  the  necessary  quantity 
of  a  hot  strong  solution  of  potassium  iodide 
(i  :  i),  the  liquid  filtered,  and  the  filtrate  mixed 
with  an  equal  quantity  of  potassium  iodide 
solution.  This  reagent  gives  red-brown  pre- 
cipitates with  various  alkaloids. 

DRAGENDORFF  (narcotine). — On  dissolving  a  little 
narcotine  in  strong  sulphuric  acid,  with  the  aid 
of  gentle  heat,  it  first  gives  a  crimson-red 
coloration,  then  forms  bluish-violet  streaks,  and 
finally  the  liquid  becomes  reddish- violet. 

DRAGENDORFF-PODWYSTOTZKI  (erithrosclerotin  in 
flour). — The  material  is  exhausted  with  alcohol 
containing  sulphuric  acid,  and  then  extracted 
with  ether.  The  extract  is  filtered,  and  the  filtrate 
is  extracted  with  sodium  bicarbonate  solution, 
and  examined  spectroscopically  whether  it  shows 
an  absorption  band  in  the  green,  and  not  in  the 
blue  part  of  the  spectrum. 

DRAPER  (castor  oil). — The  oil  is  treated  with  nitric 
acid,  and  the  acid  solution  neutralised  with 
sodium  hydroxide,  and  heated  to  boiling.  In 
the  presence  of  castor  oil  the  odour  of  cenanthic 
ether  will  be  perceptible. 

DRECHSEL  (biliary  acids  in  urine). — The  reaction 
91 


REAGENTS   AND   REACTIONS. 

is  a  modification  of  that  of  Pettenkofer,  and 
consists  in  the  use  of  phosphoric  acid  in  place  of 
sulphuric  acid.  The  chromatic  reactions  ob- 
served on  heating  the  liquid  are  the  same. 

DRECHSEL  (dextrose  in  urine}. — Ten  drops  of  the 
urine  are  made  alkaline  with  sodium  hydroxide, 
and  filtered,  and  the  nitrate  diluted  with  20  c.c. 
of  water,  and  then  boiled  for  five  minutes  with 
20  drops  of  Fehling's  solution.  Glucuronic 
acid  and  creatinine  do  not  cause  reduction  at 
such  dilution. 

DRESCHER  (alcohol  in  essential  oils). — A  solution 
of  potassium  bichromate  (i  part)  in  10  parts  of 
nitric  acid  gives,  in  the  presence  of  alcohol,  a 
pungent  odour  of  the  particular  essential  oil 
present,  and  a  distinctive  coloration. 

DUDLEY  (gallic  acid). — A  dilute  aqueous  solution 
of  picric  acid  treated  with  an  excess  of  ammonia 
gives  a  red  coloration,  changing  to  green  when 
added  to  gallic  acid. 

DUDLEY  (dextrose). — A  solution  of  basic  bismuth 
nitrate  in  a  mixture  in  equal  parts  of  nitric 
and  acetic  acids  is  cautiously  diluted  with  water, 
and  filtered  if  necessary.  The  solution  under 
examination  is  made  alkaline  with  sodium 
hydroxide,  and  heated  with  a  few  drops  of  the 
reagent.  In  the  presence  of  dextrose  a  brownish- 
black  coloration  is  obtained. 

DUFLOS  (aniline). — On  adding  dilute  sulphuric 
acid  and  lead  peroxide  to  aniline  a  green  colora- 
tion is  produced. 

DUMONT  (artificial  camphor). — A  solution  of  arti- 
ficial camphor,  or  of  natural  camphor  adulterated 
with  the  artificial  product,  gives  a  persistent 
turbidity  or  a  precipitate  with  ammonia. 

DUPONY  (boiled  and  unboiled  milk). — Fresh  un- 
boiled milk  to  which  hydrogen  peroxide  has  been 
added  gives  an  orange-yellow  coloration  with 
guaiacum  tincture,  a  red  coloration  and  forma- 
92 


REAGENTS  AND   REACTIONS. 

tion  of  green  crystals  of  quinby  drone  with 
hydroquinone,  a  bluish-violet  coloration  with 
a-naphthol  and  a  deep  violet  coloration  with 
paraphenylenediamine.  Boiled  milk  does  not 
give  these  reactions. 
DUPONY  (chloroform). — On  boiling  0-5  c.c.  of  a 

5  per  cent,  alcoholic  solution  of  thymol  for  half  a 
minute  with  i  drop  of  chloroform  and  a  little 
potassium    hydroxide     there    is    produced     a 
yellowish-red    coloration,     which     changes     to 
violet   on   the   cautious  addition    of    i   c.c.   of 
sulphuric  acid,  or  when  boiled  again. 

DURAL  (microscopic  stain). — The  reagent  consists 
of  a  solution  of  carmine  mixed  with  an  alcoholic 
solution  of  aniline  blue. 

DUSART-BLONDOT  (phosphorus). — Phosphorus  and 
phosphoric  acid  give  a  green  colour  to  a  hydrogen 
flame. 

DUYK  (dextrose). — To  25  c.c.  of  a  20  per  cent, 
solution  of  nickel  sulphate  are  added  20  c.c.  of 
sodium  hydroxide  solution  and  50  c.c.  of  a 

6  per  cent,  solution  of  tartaric  acid.    When  the 
solution  thus  prepared  (which  should  be  of  a 
pale  green  colour)  is  boiled  with  a  liquid  con- 
taining dextrose,  a  brown  or  black  coloration  will 
be  obtained. 

DUYK  (oil  of  turpentine  in  oil  of  lemon). — The 
lemon  oil  is  distilled,  and  the  first  drops  of  the 
distillate  are  collected  on  calcium  phosphate, 
which  is  then  mixed  with  water,  and  the  liquid 
filtered.  On  treating  the  filtrate  with  magenta 
decolorised  with  sulphurous  acid,  a  pink  colora- 
tion will  be  obtained  in  the  presence  of  oil  of 
turpentine. 

E. 

EBER    (tainted   meat}. — The    reagent    consists    of 
i  part  of  hydrochloric  acid,  3  parts  of  alcohol, 
93 


REAGENTS  AND   REACTIONS. 

and  i  part  of  ether.  A  fragment  of  the  meat  is 
added  to  a  few  drops  of  the  reagent  in  a  test- 
tube,  and  if  the  meat  is  unsound  a  white 
turbidity  will  be  formed  at  the  juncture  of  the 
liquids. 

EBOLI  (cantharidine). — The  test  consists  in  heating 
the  cantharidine  with  strong  sulphuric  acid 
and  a  trace  of  potassium  bichromate,  when  a 
green  coloration,  changing  in  a  few  hours  into  a 
green  turbidity,  is  obtained. 

EBSTEIN-MULLER  (pyrocatechol  in  urine). — The 
reagent  consists  of  a  dilute  solution  of  ferric 
chloride.  In  the  presence  of  pyrocatechol  the 
urine  assumes  a  green  coloration,  which  changes 
to  violet  on  the  addition  of  ammonia. 

EGGER  (free  mineral  acids) . — When  a  solution  con- 
taining free  mineral  acid  is  heated  with  cholic 
acid  and  furfural  a  red  coloration  is  obtained. 

EHRLICH  (bilirubin  in  urine). — When  equal  volumes 
of  the  urine  and  of  dilute  acetic  acid  are  mixed, 
and  the  liquid  treated  with  Ehrlich's  diazo 
reagent,  a  dark  coloration,  changing  to  violet  on 
the  addition  of  acid,  is  obtained.  On  extracting 
such  urine  with  chloroform,  and  adding  an 
equal  volume  of  the  diazo  reagent  and  of  strong 
hydrochloric  acid,  a  violet  coloration,  changing 
to  blue,  is  obtained. 

EHRLICH  (stain  for  bacteriology). — (i)  One  hundred 
parts  of  a  5  per  cent,  aqueous  solution  of  aniline 
oil  are  mixed  with  n  parts  of  a  concentrated 
alcoholic  solution  of  magenta  or  gentian  violet. 

(2)  Tri-acid  solution. — 125  grms.  of  a  saturated 
aqueous  solution  of  magenta,  and  150  grms  of  a 
saturated  aqueous  solution  of  methyl  green  are 
mixed  with  100  grms.  of  glycerin,  200  grms.  of 
absolute  alcohol,  and  300  c.c.  of  water. 

(3)  A  concentrated  aqueous  solution  of  methy- 
lene  blue. 

EHRLICH  (diazo  reaction). — According  to  Ehrlich, 
94 


REAGENTS  AND   REACTIONS. 

certain  pathological  urines  (typhus,  pulmonary 
tuberculosis,  etc.)  give  a  carmine-red  or  scarlet 
coloration  when  treated  with  a  dilute  solution 
of  diazobenzenesulphonic  acid  followed  by 
ammonia,  whereas  normal  urines  give  only  a 
yellow  coloration.  The  diazo  test  is  carried  out 
as  follows  : — Ten  c.c.  of  the  urine  are  mixed 
with  10  c.c.  of  a  5  per  cent,  solution  of  sulphanilic 
acid  and  5  per  cent,  of  officinal  hydrochloric  acid. 
The  mixture  is  treated  with  2  drops  of  a  0-5  per 
cent,  solution  of  sodium  nitrite,  and  is  then 
shaken  with  an  excess  of  ammonia. 

EHRLICH  (indican  in  urine). — The  reagent  consists 
of  a  solution  of  0-33  grm.  of  dimethylamino- 
benzaldehyde  in  50  c.c.  of  water  and  strong 
hydrochloric  acid.  On  heating  i  c.c.  of  the  urine 
with  an  equal  volume  of  the  reagent,  cooling 
the  mixture,  and  treating  it  with  dilute  potas- 
sium hydroxide  or  ammonia  solution  in  excess, 
a  bright  red  coloration  indicates  the  presence  of 
indican. 

EHRLICH  (stains  for  microscopy}. — (i)  Three  grms. 
of  haematoxylin  in  90  grms.  of  alcohol  are 
treated  with  a  mixture  of  6  grms.  of  glacial  acetic 
acid,  120  grms.  of  glycerin,  and  120  c.c.  of  water, 
saturated  with  alum. 

(2)  A  concentrated  solution  of  dahlia  violet 
in  100  c.c.  of  water,  50  c.c.  of  alcohol,  and  12  c.c. 
of  acetic  acid. 

(3)  A  solution  of  gentian  violet  in  15  c.c.  of 
alcohol  and  100  c.c.  of  aniline  water. 

EHRLICH  (acetone). — On  adding  azobenzene- 
sulphonic  acid,  and  then  alkali,  to  a  solution  of 
acetone,  an  intense  red  coloration  is  obtained. 

EHRLICH -BIONDI  (triacid  mixture). — This  is  a 
mixture  of  saturated  aqueous  solutions  of 
methyl  orange  G,  acid  magenta,  and  methyl 
green,  in  the  proportions  of  10  :  3  :  5. 

EIBART  (quinine). — On  treating  an  aqueous  solu- 
95 


REAGENTS  AND   REACTIONS. 

tion  of  quinine  first  with  bromine  water,  then 
with  a  solution  of  mercuric  cyanide,  and  lastly 
with  calcium  carbonate,  a  red  coloration  is 
obtained.  Sensitiveness  —  i  :  500,000.  Narco- 
tine  and  morphine  give  the  same  coloration, 

EINHORN  (dextrose). — The  urine  is  mixed  with 
yeast  in  a  saccharometer  vessel,  and  the  amount 
of  dextrose  is  calculated  from  the  yield  of  carbon 
dioxide  evolved. 

EISELT  (melanin  in  urine}. — The  urine  is  treated 
with  chromic  acid,  potassium  bichromate,  and 
nitric  acid,  and  a  brown  or  black  coloration  is 
obtained  in  the  presence  of  melanin. 

ELLRAM  (acetone  in  urine}. — Fifty  c.c.  of  the  urine 
are  acidified  with  4  c.c.  of  30  per  cent,  acetic 
acid,  and  part  of  the  mixture  is  distilled.  Two 
to  3  c.c.  of  the  distillate  are  treated  with  i  drop 
of  a  5  per  cent,  aqueous  solution  of  formaldehyde, 
followed  by  2  c.c.  of  strong  sulphuric  acid.  In 
the  presence  of  acetone  a  red  coloration  is  pro- 
duced at  the  zone  of  contact  of  the  liquids. 
Sensitiveness  =  i  :  2,000. 

ELLRAM  (thiocyanic  acid}. — (i)  A  blue  coloration  is 
obtained  with  a  mixture  of  vanadic  acid  and 
sulphuric  acid.  Sensitiveness  =  i  :  12,000. 

(2)  Molybdic  acid  with  sulphuric  acid  gives  a 
yellow  coloration,  changing  to  blood-red.  Sensi- 
tiveness =  i :  1,000,000. 

ELLRAM  (Copaiba  balsam}. — On  treating  the  sample 
with  a  few  drops  of  a  i  per  cent,  solution  of 
vanillin  in  strong  sulphuric  acid,  a  red,  orange,  or 
violet  coloration  is  obtained,  the  intensity  of 
which  varies  with  different  kinds  of  balsam. 
Gurjun  balsam,  colophony,  camphor,  and  alka- 
loids also  give  colour  reactions  with  this 
reagent. 

ENDEMANN  (phenols}. — The  phenol  under  examina- 
tion is  treated  with  formaldehyde,  and  evapo- 
rated to  dryness,  and  strong  sulphuric  acid  is 
96 


REAGENTS  AND   REACTIONS. 

added  to  the  residue.  The  following  colorations 
a^e  obtained  : — Phenol,  magenta  red  ;  salicylic 
acid  and  pyrogallic  acid,  red ;  eugenol  and 
hydroquinone,  brown  ;  guaiacol,  violet  ;  resor- 
cinol,  scarlet  ;  and  a-  and  /3-naphthol,  green. 

ERDMANN  (alkaloids). — The  reagent  consists  of  6 
drops  of  nitric  acid  (sp.  gr.  =  1-25)  in  100  c.c. 
of  water.  Ten  drops  of  this  solution  are  added 
to  20  grms.  of  strong  sulphuric  acid.  Many 
alkaloids  give  distinctive  colorations  with  this 
reagent.  For  example,  papaverine,  apomorphine, 
and  curarine  give  violet  colorations ;  thebaine, 
blood  red  ;  veratrine,  orange  ;  berberine,  olive- 
green  ;  digitaline,  red-brown,  changing  after 
twelve  hours  to  cherry-red  ;  morphine,  red  and 
then  greenish-brown  ;  and  piperine,  pale  yellow. 

ERDMANN  (nitrites  in  water}. — The  reagent  is  a 
solution  of  0-2  grm.  of  sodium  sulphanilate  in 
100  c.c.  of  water  containing  hydrochloric  acid. 
Fifty  c.c.  of  the  water  under  examination  are 
treated  with  5  c.c.  of  this  solution,  and  then, 
after  ten  minutes,  with  0-5  grm.  of  amino- 
naphtholdisulphonic  acid  in  the  form  of  powder. 
A  Bordeaux-red  coloration  is  obtained  in  the 
presence  of  even  traces  of  nitrous  acid. 

ERLIKI  (stain  for  microscopy}. — This  consists  of  a 
solution  of  2-5  grms.  of  methyl  green  in  100  c.c. 
of  i  per  cent,  acetic  acid. 

ERLWEIN-WEYL  (ozone}. — A  solution  of  o-i  grm. 
of  metaphenylenediamine  in  90  c.c.  of  water  and 
10  c.c.  of  5  per  cent,  sodium  hydroxide  solution 
gives  a  red  coloration  with  ozone.  Nitrous  acid 
and  hydrogen  peroxide  do  not  change  the  colour 
of  the  reagent. 

ESBACH  (albumin  in  urine}. — The  reagent  consists 
of  10  grms.  of  picric  acid,  20  grms.  of  citric 
acid,  and  970  c.c.  of  water.  In  the  presence 
of  albumin  a  yellow  precipitate  is  obtained, 
and  a  quantitative  estimation  may  be  made  by 
R.R  97  7 


REAGENTS  AND   REACTIONS. 

carrying  out  the  test  in  a  special  graduated 
apparatus. 

EYKMANN  (phenol) . — A  red  ring  is  produced  at  the 
zone  of  contact  on  adding  strong  sulphuric  acid 
to  a  solution  of  phenol  mixed  with  a  few  drops 
of  spirit  of  nitrous  ether. 

EWALD  (hydrochloric  acid  in  gastric  juice). — 
Three  drops  of  the  liquid  under  examination  are 
added  to  a  mixture  of  2  drops  of  a  10  per  cent, 
solution  of  potassium  thiocyanate  and  0-5  c.c. 
of  a  neutral  solution  of  iron  acetate,  diluted  to 
10  c.c.  In  the  presence  of  hydrochloric  acid,  a 
violet  cloud  is  produced  at  the  zone  of  contact, 
and  when  this  disappears  the  colour  of  the 
liquid  becomes  deep  brown. 

EWINS  (adrenaline}. — A  red  coloration  is  produced 
on  heating  adrenaline  with  a  o-i  per  cent, 
solution  of  potassium  persulphate.  Sensitive- 
ness =  i  :  5,000,0000. 


F. 

FABRIS  (oil  of  turpentine  in  lemon,  oil). — When 
i  to  2  c.c.  of  the  essential  oil  is  heated  with  a 
crystal  of  picric  acid  an  intense  red  coloration 
is  obtained  in  the  presence  of  oil  of  turpentine, 
but  no  coloration  with  pure  oil  of  lemon.  The 
coloration  with  turpentine  is  much  intensified  by 
dissolving  i  c.c.  of  the  oil  in  5  c.c.  of  chloroform. 

FABY  (codeine}. — A  blue  coloration  is  produced 
when  a  trace  of  codeine  is  triturated  with  2  drops 
of  sodium  hypochlorite  solution,  and  treated  with 
4  drops  of  strong  sulphuric  acid. 

FALK  (blood). — Alcohol,  chloroform,  and  ozonised 
oil  of  turpentine  (20  grms.  of  each)  are  mixed 
with  2  grms.  of  glacial  acetic  acid.  The  mixture 
is  diluted  with  water  until  a  persistent  turbidity 
is  obtained,  and  a  trace  of  guaiacum  resin  is 


REAGENTS  AND   REACTIONS. 

dissolved  in  the  solution.  This  reagent  gives  a 
blue  coloration  with  blood. 

FAURE  (colouring  matters  in  wine). — Two  c.c.  of 
the  wine  are  treated  with  10  drops  of  a  2  per 
cent,  solution  of  tannin,  and  then  with  6  drops 
of  a  6  per  cent,  solution  of  gelatin.  Natural 
colouring  matters  in  the  wine  are  precipitated, 
whilst  coal-tar  colours  are  not  affected. 

FEHLING  (dextrose). — (i)  34-639  grms.  of  crys- 
tallised copper  sulphate  are  dissolved  in  500  c.c. 
of  water.  (2)  A  solution  of  173  grms.  of  potas- 
sium sodium  tartrate  and  50  grms.  of  sodium 
hydroxide  in  500  c.c.  of  water.  Equal  parts  of 
the  two  solutions  are  used  for  the  test,  and 
10  c.c.  of  the  reagent  is  equivalent  to  5  mgrms. 
of  dextrose.  In  the  presence  of  dextrose  the 
solution  is  decolorised  on  boiling,  and  yields  a 
red  deposit  of  cupeous  oxide. 

FENTON  (tartaric  acid}. — On  adding  to  a  solution 
of  tartaric  acid,  or  a  tartrate,  a  trace  of  ferrous 
sulphate,  then  2  drops  of  hydrogen  peroxide,  and 
finally  an  excess  of  sodium  or  potassium 
hydroxide,  a  violet  coloration,  which  in  con- 
centrated solutions  becomes  black,  is  obtained. 

FERRARO  (castor  oil  in  olive  oil). — Castor  oil  will 
dissolve  a  solution  of  magenta  in  alcohol  (0-05 
per  cent,  in  absolute  alcohol).  Hence,  on 
shaking  adulterated  olive  oil  with  this  reagent 
(5  :  25),  castor  oil  will  separate,  forming  a  pink 
layer  at  the  top,  the  depth  of  which  stands  in 
relationship  to  its  quantity,  whilst  the  lower 
yellow  layer  consists  of  the  olive  oil. 

FERRARO  (santonine,  veratrine,  resorcinol). — On 
treating  a  small  quantity  of  santonine  in  a 
watch-glass  with  a  few  drops  of  sulphuric  acid 
and  with  alcohol,  a  distinctive  red  coloration  is 
obtained.  Under  the  same  conditions  veratrine 
gives  a  bright  violet  coloration,  whilst  resorcinol 
gives  first  a  yellow  coloration,  which  soon 
99  7-2 


REAGENTS  AND   REACTIONS. 

changes  to  blood-red,  but  always  shows  a 
characteristic  yellow  zone. 

FISCHER  (hydrogen  sulphide). — The  liquid  under 
examination  is  treated  with  a  tenth  of  its  volume 
of  strong  hydrochloric  acid,  and  is  then  mixed 
with  a  fragment  of  />-ammo-methylaniline,  and, 
when  this  has,  dissolved,  from  i  to  2  drops  of 
dilute  ferr;Lc  chloride  solution  are  added.  In 
the  presence  of  hydrogen  sulphide  a  pronounced 
blue  coloration  is  obtained.  The  reaction  is 
capable  of  detecting  0-0000182  grm.  of  hydrogen 
sulphide  per  litre. 

FISCHER  (cobalt  salts). — An  aqueous  solution  of 
potassium  nitrite  acidified  with  acetic  acid  gives, 
with  salts  of  cobalt,  a  yellow  precipitate  of  potas- 
sium cobaltinitrite. 

FISCHER  (sugars). — Phenyl  hydrazine  and  sodium 
acetate,  when  heated  with  sugars,  yield  crystal- 
line osazones. 

FLEISCHL  (biliary  pigments). — The  urine  is  treated 
with  a  concentrated  solution  of  sodium  nitrate, 
and  strong  sulphuric  acid  is  then  added  from  a 
pipette.  The  layer  of  acid  which  forms  at  the 
bottom  will  show  the  same  colour  reaction  as  in 
Gmelin's  test. 

FLEMMING  (fixative  for  microscopy). — This  consists 
of  a  mixture  of  10  c.c.  of  2  per  cent,  osmic  acid 
solution,  20  c.c.  of  i  per  cent,  chromic  acid 
solution,  and  10  c.c.  of  acetic  acid.  The  solution 
is  kept  in  the  dark. 

FLORENCE  (sperm  stains). — Potassium  iodide,  1-65 

§TQS.  ;    iodine,  2-54  grms.  ;    and  water,  30  c.c. 
ne  drop  of  the  reagent  added  to  the  liquid  under 
examination  forms  brown  crystals  resembling 
haemin    crystals    (reaction    of    all    substances 
containing  cholesterol). 
FLUCKIGER  (gurjun  balsam  in  copaiba  balsam). — 
A  solution  of  copaiba  balsam  in  carbon  bisul- 
phide is  shaken  with  i  drop  of  a  cold  mixture 
100 


REAGENTS  ANQf Rp^ 

of  equal  parts  of  sulphuric  and  nitric  acias.  In 
the  presence  of  gurjun  balsam  a  reddish- violet 
coloration  is  obtained. 

FLUCKIGER  (quinine). — A  solution  of  quinine  gives 
an  emerald-green  coloration  when  treated  with 
bromine  water  and  excess  of  ammonia  (thalleio- 
quin  reaction). 

FLUCKIGER  (cocaine). — On  heating  cocaine  with 
sulphuric  acid  (sp.  gr.  1-84)  white  vapours  are 
evolved,  which  on  cooling  deposit  crystals  of 
benzoic  acid. 

FLUCKIGER  (morphine). — On  adding  a  crystal  of 
morphine  to  a  mixture  of  basic  bismuth  nitrate 
and  sulphuric  acid,  the  acid  assumes  a  blackish- 
brown  colour. 

FOCKER  (uric  acid  in  urine). — The  addition  of  a 
solution  of  ammonium  chloride  to  urine,  pre- 
viously rendered  alkaline  with  sodium  hydroxide, 
produces  a  precipitate  of  acid  ammonium  urate, 
which  is  only  sparingly  soluble,  and  so  may  be 
separated  and  weighed. 

FODOR  (carbon  monoxide  in  air). — The  air  is  made 
to  pass  through  blood,  which  is  then  heated 
for  some  hours  in  the  presence  of  potassium 
hydroxide,  whilst  simultaneously  a  current  of 
air  is  passed  through  the  same  blood.  On  now 
passing  this  air  through  a  solution  of  palladium 
chloride  a  darkening  of  the  liquid  indicates  the 
presence  of  carbon  monoxide. 

FOL  (fixative  for  microscopy). — This  consists  of  a 
filtered  mixture  of  10  parts  of  a  saturated 
aqueous  solution  of  picric  acid,  25  parts  of  a 
i  per  cent,  aqueous  solution  of  chromic  acid, 
and  65  parts  of  water. 

FRANKLAND  (nitrous  acid). — The  reagent  is  a 
slightly  acid  solution  of  sulphanilic  acid  and 
phenol.  When  mixed  with  a  solution  containing 
nitrous  acid,  to  which  ammonia  is  then  added, 
a  red  coloration  is  produced. 
101 


REAGENTS  AND   REACTIONS. 

FRAUDE  (alkaloids}. — The  reagent  consists  of  an 
aqueous  solution  of  perchloric  acid  (sp.  gr.  1-13), 
which  gives  distinctive  colorations  with  certain 
alkaloids.  Aspidospermine  gives  a  magenta- 
red  coloration,  brucine  a  madder-brown,  and 
strychnine  a  yellowish-red  coloration. 

FRESENIUS  (phenols). — On  boiling  the  phenol  with 
a  solution  of  mercurous  nitrate  containing  a 
trace  of  free  acid,  an  odour  of  salicylic  aldehyde 
is  emitted,  and  metallic  mercury  separates. 

FREY  (stain  for  microscopy). — Magenta  crystals 
o-oi  grm.  ;  absolute  alcohol,  15  to  20  drops ; 
water,  15  c.c. 

FROHDE  (hydrocyanic  acid). — When  a  cyanide  is 
fused  on  platinum  foil  with  sodium  thiosulphate, 
the  mass  dissolved  in  water,  and  the  solution 
treated  with  ferric  chloride,  a  blood-red  colora- 
tion is  obtained. 

FROHDE  (alkaloids), — The  reagent  consists  of  a 
freshly-prepared  solution  of  o-oi  grm.  of  sodium 
molybdate  in  i  c.c.  of  strong  sulphuric  acid. 
It  gives  characteristic  colorations  with  certain 
alkaloids  and  glucosides.  For  example,  aconitine 
gives  a  yellowish-brown  coloration ;  brucine, 
red,  changing  to  yellow  ;  codeine,  green  and 
then  blue ;  colchicine  and  coniine,  yellow ; 
delphine,  reddish-brown  ;  digitaline,  orange  and 
then  cherry-red ;  morphine  and  papaverine, 
violet ;  solanine,  cherry-red  ;  and  thebaine,  a 
red  coloration. 

FROHDE  (biliary  pigments). — A  zone  of  a  green  to 
red  colour  is  obtained  when  the  urine  is  cau- 
tiously poured  on  to  the  surface  of  nitric  acid 
saturated  with  oxides  of  nitrogen. 

FURBRINGER  (albumin  in  urine). — The  reagent 
consists  of  a  mixture  of  mercuric  chloride, 
sodium  chloride,  and  citric  acid.  This  solution 
gives,  with  albuminous  urine,  a  turbidity  or  a 
Socculent  precipitate.  It  also  precipitates  uric 

102 


REAGENTS   AND   REACTIONS. 

acid,  and  it  is  therefore  necessary  to  dilute  the 
urine  before  applying  the  test. 


G. 

GABBET  (stain  for  bacteriology}. — One  part  of 
sulphuric  acid  is  diluted  with  3  parts  of  water, 
and  sufficient  methyl  blue  is  added  to  give  an 
intense  blue  solution. 

GAGLIO  (mercury  vapour  in  air). — An  aqueous 
0-02  per  cent,  solution  of  palladium  chloride 
turns  black,  or  becomes  turbid,  on  contact  with 
mercury  vapour. 

GALIPPE  (albumin  in  urine). — A  solution  of  picric 
acid  is  added  drop  by  drop  to  the  urine  ;  in  the 
presence  of  albumin,  a  turbidity  is  produced  on 
the  addition  of  each  drop. 

GALLOIS  (inosits  in  urine). — The  urine  is  freed 
from  dextrose  by  means  of  fermentation,  and 
from  albumin  by  boiling,  and  is  then  concen- 
trated to  a  small  volume,  and  treated  with  a 
drop  of  mercurous  nitrate  solution.  The  result- 
ing precipitate  is  dried  in  a  crucible,  and,  in  the 
presence  of  inosite,  the  dry  residue,  when  gently 
heated,  gives  a  more  or  less  intense  dark  red 
coloration. 

GANASSINI  (hydrogen  sulphide). — A  solution  of 
1-25  grms.  of  ammonium  molybdate  in  50  c.c.  of 
water  is  mixed  with  a  solution  of  2-5  grms.  of 
potassium  thiocyanate  in  45  c.c.  of  water,  and 
5  c.c.  of  strong  hydrochloric  acid  are  added  to 
the  mixture.  If  the  liquid  becomes  red,  a  small 
quantity  of  oxalic  acid  is  added  until  it  has  a 
greenish-yellow  colour.  Strips  of  paper  impreg- 
nated with  this  solution  give  an  intense  violet 
coloration  in  presence  of  hydrogen  sulphide. 

GANASSINI    (tartar ic    acid). — The   solution    to    be 
tested  for  tartaric  acid  is  boiled  with  red-lead 
103 


REAGENTS  AND  REACTIONS. 

and  filtered,  and  the  filtrate  is  treated  with  an 
equal  volume  of  20  per  cent,  potassium  thio- 
cyanate  solution,  again  boiled,  and  allowed  to 
stand.  In  the  presence  of  tartaric  acid  the 
liquid  immediately  becomes  black  owing  to  the 
formation  of  lead  sulphide. 

GAND  (dextrose). — The  reagent  consists  of  an 
ammoniacal  solution  of  copper  sulphate,  which 
when  heated  to  80°  C.,  is  decolorised  by  dextrose. 

GANNTHER  (cotton-seed  oil  in  lard). — One  c.c.  of 
the  melted  lard,  which  has  been  freed  from  water, 
is  dissolved  in  10  c.c.  of  petroleum  spirit,  and 
this  solution  is  vigorously  shaken  with  i  c.c.  of 
strong  sulphuric  acid.  In  the  presence  of  even 
i  per  cent,  of  cotton-seed  oil,  the  liquid  assumes 
an  intense  brown  colour  ;  whilst  pure  lard  gives 
only  a  yellow  coloration. 

GANNTHER  (blood).  — The  reagent  consists  of 
hydrogen  peroxide,  which  is  decomposed  by 
blood,  with  the  liberation  of  oxygen. 

GARDINER  (tannic  acids). — A  concentrated  solution 
of  ammonium  molybdate  gives  a  yellow  precipi- 
tate with  tannic  acids.  This  reagent  may  also 
be  used  in  microscopy. 

GASSEND  (sesame  oil  in  olive  oil). — The  test  is  a 
modification  of  Baudouin's  reaction.  Fifteen  c.c. 
of  the  oil  are  shaken  with  10  c.c.  of  the  hydro- 
chloric acid  solution  of  sugar,  and  then  treated 
with  2  to  3  c.c.  of  10  per  cent,  sodium  bisulphite 
solution,  and  allowed  to  stand  for  five  minutes. 
The  appearance  of  a  persistent  red  coloration 
indicates  the  presence  of  sesame  oil. 

GAUSE  (dextrose). — A  solution  of  0-5  grm.  of 
potassium  ferrocyanide  and  0-15  grm.  of  sodium 
hydroxide  in  i  litre  of  water  is  decolorised  by 
dextrose.  Each  c.c.  of  the  reagent  corresponds 
with  0-00015  grm.  of  dextrose. 

GAUTIER  (egg  albumin  and  blood  albumin). — The 
reagent  consists  of  a  mixture  of  250  c.c.  of 
104 


REAGENTS   AND   REACTIONS. 

sodium  hydroxide  solution,  50  c.c.  of  copper 
sulphate  solution,  and  700  c.c.  of  glacial  acetic 
acid.  Ten  c.c.  of  this  mixture  are  treated  with 
2  c.c.  of  the  solution  under  examination.  Egg 
albumin  gives  a  flocculent  precipitate,  whilst 
blood  albumin  does  not  produce  even  a  tur- 
bidity. 

GAWALOWSKY  (petroleum  spirit  and  benzene). — 
Picric  acid  is  soluble  in  benzene,  producing  a 
bright  yellow  solution,  whereas  it  is  only  very 
sparingly  soluble  in  petroleum  spirit,  and  without 
producing  any  appreciable  coloration. 

GAYON  (aldehydes  and  ketones). — See  SCHIFF'S 
reagent. 

GEITHERR  (cocaine). — On  mixing  a  solution  of  a 
cocaine  salt  with  2  to  3  c.c.  of  chlorine  water, 
and  then  with  a  few  drops  of  a  5  per  cent, 
solution  of  palladium  chloride,  a  red  precipitate 
is  obtained,  which  is  slowly  decomposed  by 
water. 

GENTELE  (dextrose). — The  reagent  is  identical  with 
that  of  GAUSE.  It  should  be  noted,  moreover, 
that  uric  acid  gives  the  same  reaction  as 
dextrose. 

GERHARDT  (aceto-acetic  acid  in  urine). — The  re- 
action consists  in  the  red  coloration  which  urine 
containing  this  acid  or  its  esters  gives  with 
ferric  chloride.  Recently  lastrowitz  has  recom- 
mended the  following  modification  : — The  urine 
is  treated  with  a  dilute  solution  of  ferric  chloride 
in  such  a  way  that  the  two  layers  do  not  mix, 
and  that  the  ferric  chloride  solution  is  of  greater 
density.  To  ensure  this,  6  c.c.  of  water  are 
mixed  with  6  to  20  drops  of  ferric  chloride 
solution,  according  to  the  density  of  the  urine, 
and  i  grm.  of  the  urine  is  run  on  to  the  surface 
of  the  solution  by  means  of  a  pipette.  In  the 
presence  of  aceto-acetic  acid  a  red  ring  is  formed 
at  the  zone  of  contact. 
105 


REAGENTS  AND   REACTIONS. 

GERHARDT  (biliary  pigments  in  urine). — The  urine 
is  extracted  with  chloroform,  and  the  extract  is 
mixed  with  ozonised  oil  of  turpentine,  and  with 
a  little  dilute  potassium  hydroxide  solution.  In 
the  presence  of  biliverdine  a  green  coloration  is 
produced  in  the  aqueous  layer.  On  then  treating 
the  chloroform  extract  with  iodine,  and  adding 
an  excess  of  potassium  hydroxide,  the  aqueous 
layer  is  coloured  yellow,  with  green  fluorescence, 
when  urobilin  is  present. 

GERRARD  (atr opine). — The  reagent  consists  of  a 
solution  of  5  grms.  of  mercuric  chloride  in 
95  grms.  of  50  per  cent,  alcohol.  On  heating 
i  mgrm.  of  atropine  with  2  c.c.  of  this  reagent, 
a  red  precipitate  of  mercuric  oxide  is  obtained. 
The  reaction  is  produced  only  by  the  free  base, 
and  not  by  its  salts. 

GERRARD  (dextrose). — Fehling's  solution  is  treated 
with  50  per  cent,  potassium  cyanide  solution 
until  decolorised,  and  then  mixed  with  an  equal 
volume  of  fresh  Fehling's  solution.  The  blue 
solution  thus  obtained  is  quantitatively  decom- 
posed when  boiled  with  dextrose. 

GIBBE  (microscopic  stain). — A  mixture  of  2  grms. 
of  magenta  and  i  grm.  of  methylene  blue  is 
ground  up,  and  treated  with  3  c.c.  of  aniline  oil 
dissolved  in  15  c.c.  of  alcohol.  Finally,  15  c.c. 
of  water  are  added,  and  the  solution  is  kept  in 
well-closed  bottles. 

GIEMSA  (stain  for  microscopy). — Azure  blue,  II.,  3 
grms.  ;  eosin  (B.A.),  0-8  grm.  ;  pure  glycerin, 
250  c.c.  ;  and  methyl  alcohol,  250  c.c. 

GIESEL  (cocaine). — On  adding  to  a  concentrated 
solution  of  a  cocaine  salt  a  i  per  cent,  solution 
of  potassium  permanganate,  drop  by  drop,  a 
crystalline  violet  precipitate  of  cocaine  per- 
manganate is  obtained. 

GIGLI    (uric   acid). — Five   c.c.    of   the   urine    are 
treated  with  a  nitric  acid  solution  of  ammo- 
106 


REAGENTS  AND   REACTIONS. 

nium  molybdate.  If  a  greenish  precipitate  is 
obtained,  and  this  is  treated  with  ammonia  or 
sodium  hydroxide  solution  until  redissolved,  a 
clear  blue  solution  will  be  obtained. 

GILLET-HAIN  (ketones). — Aqueous  solutions  of 
ketones  yield  yellow  crystalline  precipitates  with 
Nessler's  reagent. 

GIRARD  (coal-tar  colours  in  wine). — Twenty  c.c. 
of  the  wine  are  treated  with  4  c.c.  of  10  per  cent, 
potassium  hydroxide  solution,  and  20  c.c.  of 
5  per  cent,  mercuric  sulphate  solution.  Genuine 
wines  yield  a  colourless  filtrate,  whilst  those 
containing  coal-tar  dyes  give  a  red  nitrate. 

GLUZINSKY  (biliary  pigments  in  urine). — A  solution 
of  a  biliary  pigment  gives,  when  boiled  with 
formaldehyde,  an  emerald-green  coloration, 
which  becomes  amethyst-blue  on  the  addition 
of  hydrochloric  acid.  When  extracted  with 
chloroform,  the  green  extract  becomes  amethyst- 
blue  if  biliverdine  alone  was  present. 

GMELIN  (biliary  pigments  in  urine). — The  liquid 
containing  the  pigments  is  treated  with  nitric 
acid  containing  nitrogen  oxides,  in  such  a  way 
that  the  two  liquids  do  not  mix,  and  that  the 
acid  falls  to  the  bottom.  At  the  zone  of  contact 
of  the  two  liquids  there  is  formed  a  ring,  which 
gradually  changes  to  the  following  colours  :— 
Green,  blue,  violet,  red,  yellow,  in  the  pro- 
gressive oxidation  of  the  bilirubin  and  biliverdine. 

GODEFROY  (alkaloids). — A  solution  of  antimony 
trichloride  gives  a  white  or  yellow  precipitate 
with  solutions  of  the  hydrochlorides  of  aconitine, 
atropine,  quinine,  cinchonine,  piperine,  strych- 
nine and  veratrine. 

GODEFROY  -  LAUBENHEIMER  (alkaloids) .  —  Silico- 
tungstic  acid  gives  precipitates  when  added 
to  ( the  solution  of  hydrochlorides  of  many 
alkaloids. 

GOLDMANN  (salophen). — On  heating  a  little  salo- 
107 


REAGENTS  AND   REACTIONS. 

phen  with  2  per  cent,  sodium  hydroxide  solution 
a  blue  coloration  is  obtained. 

GOLDSCHMIDT  (formaldehyde).- — When  a  solution 
containing  formaldehyde  is  heated  with  hydro- 
chloric acid  and  a-a-methylphenyl-hydrazine, 
a  deep  green  coloration  is  produced. 

GOLGI  (chrome-silver  microscopic  reagent}. — The 
preparation  is  fixed  by  treatment  for  a  week  in 
the  dark  with  I  per  cent,  osmic  acid  (2  parts) 
and  Muller's  solution  (8  parts)  ;  then  washed 
with  water,  stained  with  0-5  per  cent,  silver 
nitrate  solution,  which  is  renewed  until  it 
remains  clear  for  a  week,  and  treated  with 
creosote  and  Canada  balsam. 

GOPPELSRODER  (aluminium  salts}. — An  alcoholic 
solution  of  morine  gives  a  green  fluorescence, 
even  with  traces  of  a  neutral  salt  of  aluminium. 

GORUP-BESANEZ  (peptones}. — The  test  is  a  modifi- 
cation of  the  biuret  reaction. 

Gosio  (arsenic). — Arsenical  compounds  are  decom- 
posed by  Penicillium  brevicaule,  with  the  evolu- 
tion of  ethylarsine  (garlic-like  odour). 

GOUVER  (albumin  in  urine}. — The  reagent  consists 
of  a  solution  of  mercuric  cyanide  in  excess  of 
potassium  iodide  solution.  It  precipitates 
albumin  from  urine  as  a  white  precipitate. 

GRAHE  (cinchona  bark). — Cinchona  bark",  con- 
taining quinine,  cinchonidine  and  its  isomers, 
emits  carmine-red  vapours  when  heated  in  a 
test  tube. 

GRAHM  (stain  for  bacteriology}. — The  following 
solutions  are  required  : — (a)  Gentian  violet  or 
methyl  violet  in  aniline  water  ;  (b)  a  solution  of 
2  grms.  of  potassium  iodide,  and  i  grm.  of 
iodine  in  300  c.c.  of  water  ;  (c)  absolute  alcohol ; 
(d  an  alcoholic  solution  of  safranine,  vesuvine, 
or  magenta. 

GRANDEAU  (digitalin  and  digitalein}. — These  com- 
pounds give  a  yellow  coloration  on  treatment 
108 


REAGENTS  AND   REACTIONS. 

with  strong  sulphuric  acid,  and  the  colour 
changes  to  red  under  the  influence  of  bromine 
vapour.  Digitonin  and  digitoxin  do  not  give 
this  reaction. 

GRANDVAL-LAYOUX  (nitric  acid). — One  hundred  c.c. 
of  the  liquid  are  evaporated  to  dryness,  and  the 
residue  is  treated  with  10  drops  of  a  mixture  of 
7-5  grms.  of  phenol  and  52-5  grms.  of  sulphuric 
acid.  The  product  of  this  reaction  is  treated 
with  ammoniacal  water,  and,  if  nitric  acid  is 
present,  a  yellow  coloration,  due  to  the  formation 
of  picric  acid,  is  obtained.  This  reaction  has 
been  suggested  for  the  detection  of  nitric  acid 
in  drinking  water. 

GRASSINI  (alcohol). — Two  c.c.  of  a  5  per  cent, 
solution  of  cobalt  chloride  are  mixed  with  2  c.c. 
of  a  potassium  thiocyanate  solution,  and  the 
liquid  under  examination  is  added  so  as  to  form 
a  separate  layer.  In  the  presence  of  alcohol  the 
supernatant  liquid  soon  becomes  of  an  intense 
blue  colour  ;  in  some  cases  the  coloration  is 
produced  at  the  zone  of  contact. 

GRENACHER  (stain  for  microscopy). — (i)  A  little 
carmine  is  dissolved  in  50  c.c.  of  60  to  80  per 
cent,  alcohol,  3  to  4  drops  of  hydrochloric  acid 
added,  and  the  liquid  filtered.  (2)  From  2  to 
3  grms.  of  carmine,  and  4  grms.  of  borax  are 
dissolved  in  100  c.c.  of  boiling  water,  and  the 
solution  diluted  with  an  equal  volume  of  70  per 
cent,  alcohol,  and  filtered  after  standing  for  a 
long  time. 

GRIESS  (nitrous  acid). — The  original  reagent  con- 
sisted of  phenylenediamine,  which  gives  a 
yellow  coloration  with  nitrous  acid.  The 
modification  of  Ilosvay  and  Lunge,  however, 
is  also  known  as  Griess's  reagent ;  it  is  prepared 
as  follows : — A  solution  of  0-5  grm.  of  sul- 
phanilic  acid  in  150  c.c.  of  dilute  acetic  acid  is 
mixed  with  a  solution  prepared  by  boiling 
109 


REAGENTS   AND   REACTIONS. 

0-2  grm.  of  solid  a-naphthylamine  with  20  c.c. 
of  water,  decanting  the  colourless  liquid,  and 
adding  it  to  150  c.c.  of  dilute  acetic  acid.  On 
adding  2  c.c.  of  the  reagent  to  50  c.c.  of  a 
solution  containing  nitrous  acid  a  bright  red 
coloration  is  obtained. 

GRIMBERT-LECLERC  (apomorphine) . — Five  c.c.  of 
the  solution  are  treated  with  5  drops  of  a 
saturated  solution  of  mercuric  chloride  and 
5  drops  of  a  10  per  cent,  solution  of  sodium 
acetate,  and  the  liquid  cooled,  and  treated  with 
i  to  2  c.c.  of  amyl  alcohol.  In  the  presence  of 
apomorphine  the  amyl  alcohol  becomes  of  an 
intense  blue  colour.  Sensitiveness  =  i  :  100,000. 

GROSSMANN  (salts  of  nickel). — A  solution  of 
dicyano-diamidine  is  heated  to  boiling  point 
with  a  few  drops  of  hydrochloric  acid,  the 
solution  to  be  tested  for  nickel  then  added,  and, 
finally,  potassium  hydroxide.  In  the  presence 
of  an  appreciable  amount  of  nickel,  a  yellow 
cystalline  precipitate  is  obtained  ;  otherwise  it 
is  formed  after  some  time.  The  precipitate  is 
insoluble  in  ammonia  solution,  but  dissolves  in 
potassium  cyanide  solution. 

GRUNHAT  (glycerin). — On  heating  glycerin  with 
potassium  bisulphate,  acrolein  is  formed,  and 
emits  a  characteristic  pungent  odour.  If  the 
vapours  evolved  be  passed  through  an  ammonia- 
cal  solution  of  silver  nitrate,  metallic  silver 
separates. 

GUARESCHI  (alkaloids). — The  reagent  consists  of 
potassium  platino-thiocyanate,  which  is  pre- 
pared by  adding  4  or  5  drops  of  chloroplatinic 
acid  to  a  solution  of  4  grms.  of  potassium  thio- 
cyanate.  A  5  per  cent,  solution  of  the  salt  gives 
a  precipitate  with  various  alkaloids. 

GUARESCHI  (bromine). — Free  bromine  imparts  an 
intense  violet-blue  coloration  to  Schiff  s  reagent 
(magenta  decolorised  by  SO2).    The  reaction  is 
no 


REAGENTS   AND   REACTIONS. 

extremely  sensitive,  a  coloration  being  given 
by  i  drop  of  bromine  water  (i  :  1,000)  in  i  c.c. 
of  water. 

GUARESCHI  (phenol). — On  heating  phenol  with 
potassium  hydroxide  and  chloroform,  a  red  mass, 
dissolving  in  alcohol  to  form  a  red  solution,  is 
obtained. 

GUERIN  (albumin  in  urine). — The  reagent  consists 
of  a  10  per  cent,  alcoholic  solution  of  sozo- 
iodolic  acid.  On  adding  10  drops  of  the  reagent 
to  10  c.c.  of  albuminous  urine  a  white  precipitate, 
which  does  not  disappear  on  heating,  is  obtained. 

GUNNING  (acetone). — The  test  depends  on  the 
formation  of  iodoform  when  tincture  of  iodine 
and  ammonia  solution  are  added  to  the  liquid 
under  examination. 

GUNN-HARRISON  (adrenalin). — Traces  of  adrenalin 
(fractions  of  a  mgrm.)  emit  an  odour  of  methy- 
lamine  when  treated  with  5  drops  of  10  per  cent, 
sodium  hydroxide  solution. 

GUNZBURG  (hydrochloric  acid  in  gastric  juice] . — The 
reagent  consists  of  a  solution  of  2  grms.  of  phloro- 
glucinol  and  i  grm.  of  vanillin  in  30  grms.  of 
absolute  alcohol.  A  few  drops  of  this  solution 
are  evaporated  with  the  same  quantity  of 
filtered  gastric  juice  in  a  porcelain  crucible.  In 
the  presence  of  free  hydrochloric  acid  a  red  layer 
is  formed.  Should  the  acid  be  present  in  the 
proportion  of  i:  10,000  red  crystals  are  pro- 
duced, whilst  in  the  proportion  of  i  :  20,000  only 
red  streaks  appear. 

GUTZEIT  (arsenic) . — Paper  impregnated  with  silver 
nitrate  turns  yellow  with  black  margin,  in  the 
presence  of  arsine. 

H. 

HABERMANN  (carbon  monoxide}. — An  ammoniacal 
solution  of  silver  nitrate  is  reduced  by  carbon 
in 


REAGENTS   AND   REACTIONS. 

monoxide.  The  reaction  may  be  used  for  the 
detection  of  carbon  monoxide  in  air. 

HAGER  (free  mineral  acids  in  vinegar). — Twenty  c.c. 
of  the  vinegar  are  evaporated  on  the  water-bath 
with  5  c.c.  of  ammonia  solution.  In  the  presence 
of  free  mineral  acids,  a  crystalline  residue  will  be 
left. 

HAGER  (alkaloids). — The  reagent  consists  of  a 
saturated  solution  of  picric  acid. 

HAGER  (cholesterol). — A  chloroform  solution  of 
cholesterol  gives  a  red  coloration  on  the  addition 
of  sulphuric  acid. 

HAGER  (dextrose}. — Thirty  grms.  of  red  mercuric 
oxide,  30  grms.  of  sodium  acetate,  and  50  grms. 
of  sodium  chloride  are  dissolved,  with  the  aid  of 
gentle  heat,  in  25  grms.  of  glacial  acetic  acid  and 
400  c.c.  of  water,  and  the  solution  diluted  to 
i  litre.  The  mercury  compound  is  reduced  by 
dextrose  on  heating. 

HAGER  (sugar  in  glycerin). — Glycerin  containing 
sugar  gives  an  intense  blue  coloration  when 
boiled  with  ammonium  molybdate  and  nitric 
acid. 

HAGER-GAWALOWSKY  (dextrose}. — The  reagent  con- 
sists of  ammonium  molybdate  in  neutral  aqueous 
solution.  It  gives  a  blue  coloration  when  boiled 
with  dextrose  in  the  presence  of  acid.  The  same 
reaction  is  also  obtained  with  cane  sugar. 

HAINE  (dextrose}. — Copper  sulphate,  3  grms.  ; 
potassium  hydroxide,  9  grms.  ;  glycerin, 
100  grms.  ;  and  water,  600  c.c.  When  heated 
with  dextrose  the  well-known  red  precipitate  is 
obtained. 

HALPHEN  (cotton-seed  oil  in  olive  oil) . — Equal  parts 
of  amyl  alcohol  and  carbon  bisulphide  are  mixed, 
and  an  excess  of  sulphur  is  added  to  the  solution. 
The  filtered  fat,  or  oil,  is  mixed  with  an  equal 
volume  of  the  reagent,  and  heated  for  fifteen 
minutes  to  one  and  a  half  hours  in  a  flask  fitted 

112 


REAGENTS  AND   REACTIONS. 

with  a.  reflux  condenser,  and  immersed  in  a 
vigorously-boiling  salt-water-bath.  If  during 
this  time  the  liquid  becomes  pink  or  red,  cotton- 
seed oil  is  present. 

HAMILTON  (microscopic  stain). — Haematoxylin,  12 
grms.  ;  ammonium  alum,  50  grms.  ;  glycerin, 
65  c.c.  ;  and  water,  130  c.c.  These  are  boiled 
together,  and  5  c.c.  of  melted  phenol  are  added 
to  the  liquid. 

HAMMARSTEN  (albumin). — A  violet  coloration  is 
obtained  on  heating  a  mixture  of  i  part  of  sul- 
phuric acid  and  2  parts  of  acetic  acid  with  albu- 
min. 

HAMMARSTEN  (biliary  pigments}. — One  part  of 
nitric  acid  is  mixed  with  19  parts  of  hydrochloric 
acid,  and  the  mixture  allowed  to  stand  until  it 
becomes  yellow.  Before  applying  the  test  the 
reagent  is  mixed  with  5  parts  of  95  per  cent, 
alcohol.  In  the  presence  of  biliary  pigments  a 
green  coloration  is  obtained. 

HAMMARSTEN- JAFF^  (indican  in  urine}. — The  urine 
is  mixed  with  an  equal  volume  of  fuming  nitric 
acid,  a  concentrated  solution  of  calcium  hypo- 
chlorite  added,  drop  by  drop,  and  the  mixture 
is  shaken  with  chloroform.  Indican,  when 
present,  is  extracted,  and  indigo,  recognisable  by 
its  blue  colour,  is  formed.  In  the  presence  of 
excess  of  hypochlorite  the  blue  colour  dis- 
appears, owing  to  the  formation  of  isatin. 

HANSTEIN  (stain for  microscopy}. — This  is  a  solution 
in  strong  alcohol  of  i  grm.  of  methyl  violet  and 
2  grms.  of  magenta. 

HANUS  (iodine  absorption). — Iodine  monobromide, 
prepared  by  slowly  adding  13  grms.  of  bromine 
to  20  grms.  of  finely -powdered  iodine  and  keeping 
the  temperature  below  8°  C.  The  excess  of 
bromine  is  expelled  by  means  of  carbon  dioxide. 
The  reagent  consists  of  a  solution  of  10  grms.  of 
the  bromide  in  500  c.c.  of  glacial  acetic  acid. 
R.R.  113  8 

COLLEGP 


REAGENTS  AND   REACTIONS. 

HAUCHECORNE  (foreign  oils  in  olive  oil). — Six  grms. 
of  the  oil  are  vigorously  shaken  for  two  minutes 
with  2  parts  of  nitric  acid  free  from  nitrogen 
oxides  (3  parts  of  nitric  acid  of  40°  Be.  and  i  part 
of  water) ,  and  a  note  is  taken  of  the  colour  of  the 
oil  immediately  after  the  agitation,  and  after  the 
test-tube  has  stood  for  twenty  minutes  in  boiling 
water.  Sesame,  cotton-seed,  linseed,  rape  oils, 
etc.,  give  an  orange  to  red-brown  coloration, 
whilst  olive  and  arachis  oils  remain  nearly 
colourless  if  fresh,  or  become  yellow  to  orange  if 
rancid. 

HAUSSLER  (citric  acid). — When  an  alcoholic  solution 
of  vanillin  is  allowed  to  evaporate  spontaneously 
in  presence  of  citric  acid  and  the  residue  is 
treated  with  a  few  drops  of  sulphuric  acid  and 
heated,  an  intense  green  coloration  is  obtained, 
which  changes  to  red  on  the  addition  of  ammonia. 

HEGLER  (ligniri). — The  sections  are  immersed  in 
alcohol,  and  then  treated  with  a  solution  of 
thallium  sulphate  in  dilute  alcohol.  Lignin 
assumes  an  orange-yellow  colour,  whilst  cellulose 
and  sugar  remain  colourless. 

HEHNER  (formaldehyde  in  milk). — Strong  sulphuric 
acid  is  added  to  the  milk  so  that  the  liquids  do 
not  mix,  and  in  presence  of  formaldehyde  a  blue 
ring  is  produced  at  the  zone  of  contact.  This 
reaction  is  not  produced  by  sulphuric  acid  free 
from  iron.  Again,  if  the  distillate  from  the  milk 
be  treated  with  i  drop  of  a  solution  of  phenol,  and 
poured  on  to  the  surface  of  strong  sulphuric  acid, 
a  carmine-red  will  be  obtained  at  the  zone  of 
contact.  Sensitiveness  =  i  :  200,000. 

HELLER  (albumin  in  urine). — The  urine  is  treated 
with  nitric  acid  in  such  a  way  as  not  to  mix  the 
two  liquids.  In  the  presence  of  albumin  a  white 
ring  is  formed  at  the  zone  of  contact. 

HELLER  (blood  in  urine). — The  urine  is  rendered 
strongly  alkaline,  and  heated ;  and,  in  the 
114 


REAGENTS  AND   REACTIONS. 

presence  of  blood,  phosphates,  coloured  red  by 
haematin,  are  precipitated. 

HERAPATH  (quinine). — An  alcoholic  solution  of 
quinine  gives  a  crystalline  precipitate  when 
treated  with  4  drops  of  tincture  of  iodine.  At 
the  ordinary  temperature  green  plates  are 
formed,  whilst  the  crystals  formed  at  100°  C.  are 
reddish-brown,  and  have  a  polarising  capacity. 

HERBST  (aconitine). — On  evaporating  aconitine 
with  phosphoric  acid  on  the  water-bath  a  violet 
coloration  is  produced. 

HERMANN  (natural  and  artificial  silk). — (i)  Arti- 
ficial silk  is  insoluble  in  an  alkaline  copper 
solution  containing  glycerin  (copper  sulphate, 
10  grms.  ;  water,  100  c.c.  ;  glycerin,  5  grms.  ; 
and  sufficient  potassium  hydroxide  to  redissolve 
the  precipitate) .  Natural  silk  is  insoluble  in  this 
reagent. 

(2)  Artificial  silk  of  the  nitrocellulose  type 
gives  a  nitric  acid  reaction  with  diphenylamine 
and  brucine  ;  whilst  natural  silk  does  not  show 
this  reaction. 

HEYDENREICH  (foreign  oils  in  olive  oil). — From 
5  to  6  drops  of  the  oil  are  made  to  fall  on  to  5  c.c. 
of  sulphuric  acid  (60°  Be.)  in  a  flat-bottomed 
porcelain  dish.  Various  colorations  are  pro- 
duced at  the  zone  of  contact  between  the  oil  and 
the  acid.  Drying  oils  give  brown  to  black 
colorations,  semi-drying  oils,  orange  to  brown 
colorations,  whilst  olive  oil  gives  no  coloration. 

HILGER  (albumin  in  urine). — A  white  precipitate 
is  formed  on  the  addition  of  acetic  acid  and 
potassium  ferrocyanide. 

HILGER  (biliary  pigments). — These  are  precipitated 
by  adding  barium  chloride  and  sulphuric  acid, 
or  by  boiling  the  liquid  with  barium  hydroxide. 
The  yellow  precipitate  is  decolorised  when 
treated  with  alcohol  containing  a  few  drops  of 
sulphuric  acid,  and  gives  a  green  solution. 
115  8-2 


REAGENTS  AND   REACTIONS. 

HILGER  (malic  acid] . — The  reaction  is  based  on  the 
precipitation  of  metallic  palladium  from  neutral 
solutions  of  palladium  chloride  by  malic  acid. 
It  is  quantitative. 

HIRSCHSOHN  (Gurjun  balsam  in  Copaiba  balsam). — 
Eight  drops  of  the  balsam  are  added  to  a  mixture 
of  2  drops  of  strong  sulphuric  acid  and  4  c.c.  of 
acetic  acid.  A  violet  coloration  indicates  the 
presence  of  Gurjun  balsam. 

HIRSCHSOHN  (quinine  and  quinidine).  --  When 
neutral  solutions  of  the  sulphate  or  chloride  of 
these  bases  are  heated  with  i  drop  of  hydrogen 
peroxide  and  a  10  per  cent,  solution  of  copper 
sulphate,  an  intense  raspberry-red  coloration  is 
produced. 

HIRSCHSOHN  (aloes). — About  10  c.c.  of  a  o-i  per 
cent,  solution  of  aloes  are  treated  with  i  drop  of 
a  10  per  cent,  solution  of  copper  sulphate  and 
I  drop  of  hydrogen  peroxide.  A  red  coloration 
is  produced  on  heating  the  mixture. 

HIRSCHSOHN  (cotton-seed  oil). — Five  c.c.  of  the  oil 
are  heated  for  twenty  minutes  on  the  water-bath 
with  10  drops  of  a  solution  of  i  grm.  of  gold 
chloride  in  200  c.c.  of  chloroform.  In  the 
presence  of  cotton-seed  oil  a  red  coloration  is 
obtained. 

HISTED  (nataloin). — On  dissolving  this  substance 
in  strong  sulphuric  acid,  and  treating  the  solution 
with  a  crystal  of  potassium  nitrate,  there  is  pro- 
duced a  green  coloration,  changing  to  red  and 
then  to  blue. 

HLASIWETZ  (hydrocyanic  acid). — This  is  the  well- 
known  reaction  of  isopurpuric  acid,  which  is  the 
cause  of  the  blood-red  coloration  obtained  on 
heating  a  solution  of  an  alkali  cyanide  with  picric 
acid. 

HOFFMANN  (aniline). — When  aniline  is  gently 
heated  with  fuming  nitric  acid  the  mixture 
becomes  blue  and  then  red,  and  crystals  of 
116 


REAGENTS   AND   REACTIONS. 

picric  acid  are  deposited,  with  the  evolution 
of  gas. 

HOFFMANN  (nitric  acid}. — This  is  the  well-known 
reaction  with  diphenylamine  and  strong  sul- 
phuric acid  (blue  coloration). 

HOFFMANN  (phenol).  —  An  aqueous  solution  of 
phenol  gives  a  violet  coloration  when  treated  with 
i  to  2  c.c.  of  sulphuric  acid  and  a  crystal  of 
potassium  nitrate. 

HOFFMANN  (tyrosin) . — The  sediment  from  the  urine 
is  heated  with  water,  and  meanwhile  treated 
with  mercuric  nitrate  solution.  In  the  presence 
of  tyrosin  the  liquid  assumes  a  purple-red  colour 
and  gives  a  red  precipitate. 

HOFFMANN  (ergot  of  rye  in  flour). — Ten  grms.  of  the 
flour  are  shaken  with  20  c.c.  of  ether  and  I  c.c.  of 
sulphuric  acid,  the  extract  filtered,  and  the  filtrate 
mixed  with  0-5  grm.  of  sodium  bicarbonate.  In 
the  presence  of  ergot  the  liquid  shows  a  violet 
coloration. 

HOFFMANN  (chloroform). — On  heating  chloroform 
with  a  few  drops  of  aniline  and  alcoholic  potas- 
sium hydroxide  solution,  the  unpleasant  odour  of 
isonitrile  is  perceptible. 

HOFFMEISTER  (leucine) . — The  solution  is  heated 
with  mercurous  nitrate,  and  in  the  presence  of 
leucine  metallic  mercury  is  precipitated. 

HOHNEL  (VON)  (ligniri). — A  concentrated  solution 
of  phenol  in  strong  hydrochloric  acid  gives  a 
green  coloration  with  lignin. 

HOPPE-SEYLER  (phenol}. — The  reaction  consists  in 
the  blue  coloration  given  by  a  section  of  pine- 
wood  when  moistened  with  hydrochloric  acid  in 
presence  of  phenol. 

HOPPE-SEYLER  (dextrose  in  urine). — Five  c.c.  of  a 
0-5  per  cent,  solution  of  ortho-nitrophenyl- 
propionic  acid  in  sodium  hydroxide  solution  is 
heated  to  boiling  with  a  few  drops  of  the  urine. 
In  the  presence  of  dextrose  the  liquid  becomes 
117 


REAGENTS   AND   REACTIONS. 

blue,  owing  to  the  formation  of  indigo  (see 
BAEYER). 

HOPPE-SEYLER  (carbon  monoxide  in  blood}. — When 
blood  is  mixed  with  an  equal  volume  of  strong 
sodium  hydroxide  solution,  it  slowly  gives  a 
bright  red  coloration,  which  changes  to  greenish- 
brown. 

HOPPE-SEYLER  (biliary  pigments  in  urine). — The 
urine  is  treated  with  milk  of  lime,  the  lime 
removed  by  means  of  carbon  dioxide,  and  the 
precipitate  collected  and  washed.  On  now 
adding  to  this  precipitate  a  few  c.c.  of  nitric  acid, 
containing  nitrous  acid,  characteristic  colorations 
are  produced  (see  GMELIN). 

HOPPE-SEYLER  (xanthin). — On  mixing  a  little 
calcium  chloride  with  sodium  hydroxide,  and 
adding  a  little  xanthin,  there  is  formed  a  green 
layer,  changing  to  brown,  and  soon  disappearing. 

HORSLY  (nitric  acid). — Nitric  acid  gives  a  violet 
coloration  when  treated  with  pyrogallic  acid  and 
sulphuric  acid. 

HUBER  (free  mineral  acids). — Mineral  acids  produce 
in  a  solution  of  ammonium  molybdate  and 
potassium  ferrocyanide,  a  reddish-brown  tur- 
bidity, or  a  precipitate  (boric  and  arsenic  acids 
are  exceptions). 

HUBL  (VON)  (iodine  absorption). — Two  solutions 
are  prepared  : — (a)  25  grms.  of  iodine  in  500  c.c. 
of  95  per  cent,  alcohol ;  (b)  30  grms.  of  mercuric 
chloride  in  500  c.c.  of  95  per  cent,  alcohol.  The 
solutions  are  mixed  before  use. 

HUFFNER  (urea). — Freshly-prepared  hypobromite 
(i  part  of  bromine  +  10  of  30  per  cent,  sodium 
hydroxide  solution)  liberates  nitrogen,  which 
may  be  quantitatively  estimated. 

HUHNEFELD  (blood  in  urine). — The  reaction  is 
similar  to  that  of  Schonbein  with  guaiacum 
resin  and  oil  of  turpentine. 

HUPPERT  (biliary  pigments  in  urine). — The  pre- 
118 


REAGENTS   AND   REACTIONS. 

cipitate  obtained  by  adding  milk  of  lime  to  the 
urine  is  extracted  with  hot  alcohol  containing 
sulphuric  acid,  and  gives  a  green  extract. 

HUSEMANN  (hydrocyanic  acid). — This  is  the  well- 
known  Prussian  blue  reaction. 

HUSEMANN  (morphine). — When  morphine  is  heated 
to  150°  C.  with  strong  sulphuric  acid,  and  a  drop 
of  nitric  acid  is  added,  an  intense  violet  colora- 
tion, changing  to  red,  is  obtained. 


I. 

IHL  (dextrose). — Dextrose,  like  dextrin,  decolorises 
a  solution  of  methylene  blue  treated  with 
sodium  carbonate. 

IHL  (beetroot  sugar). — (i)  The  sugar  is  boiled 
with  a  little  hydrochloric  acid,  and,  when  cold, 
is  treated  with  resorcinol  and  strong  sulphuric 
acid.  The  liquid  is  always  coloured  red,  and 
subsequently  yields  a  red  flocculent  precipitate. 

(2)  On  boiling  a  solution  of  the  sugar  with 
an  alcoholic  solution  of  orcinol  and  hydrochloric 
acid,  a  yellow  coloration  is  obtained,  and  on 
diluting  the  liquid  with  water,  a  green  precipitate 
is  formed. 

(3)  The    sugar    solution    gives    a    violet-red 
coloration    on    the    addition    of    an    alcoholic 
solution  of  a-naphthol  and  strong  sulphuric  acid. 

ILOSVAY  (nitrous  acid). — See  GRIESS. 

ILOSVAY  (hydrogen  peroxide). — Five  drops  of 
dimethylaniline  and  0-03  grm.  of  potassium 
bichromate  are  dissolved  in  a  litre  of  water.  On 
treating  5  c.c.  of  hydrogen  peroxide  with 
5  c.c.  of  the  reagent  and  i  drop  of  5  per  cent, 
oxalic  acid  solution  a  yellow  coloration  is  pro- 
duced. Sensitivenss  =  i  :  5,000,000. 

INCE  (nitric  acid). — Five  c.c.  of  a  solution  of 
sodium  sulphophenolate  are  mixed  with  5  c.c. 
119 


REAGENTS  AND   REACTIONS. 

of  strong  sulphuric  acid,  and  this  mixture  is 
added  to  the  liquid  under  examination  so  that 
the  two  liquids  remain  separate.  In  the  presence 
of  nitric  acid  a  red-brown  ring  is  obtained. 
Sensitiveness  =  I  :  30,000. 

IPSEN  (carbon  monoxide  in  blood}. — The  blood  is 
treated  with  a  few  drops  of  sodium  hydroxide 
solution,  and  then  with  powdered  dextrose. 
Normal  blood  rapidly  turns  brown,  whilst  blood 
containing  carbon  monoxide  becomes  bright 
red. 

ITALLIE  (VAN)  (salicylic  acid). — On  heating  a 
solution  of  sodium  salicylate  with  potassium 
nitrite  and  dilute  sulphuric  acid  a  yellow  colora- 
tion, changing  to  brown,  is  obtained.  On 
adding  a  few  drops  of  sodium  hydrochlorite 
solution,  there  is  produced  a  bright  green  colora- 
tion, which  changes  to  red  when  the  liquid  is 
treated  with  an  excess  of  acid. 

ITTNER  (hydrocyanic  acid). — Prussian  blue  is 
formed  when  a  solution  of  an  alkali  cyanide  is 
treated  with  potassium  hydroxide  and  an  iron 
salt,  and  the  liquid  acidified  with  hydrochloric 
acid. 

j. 

JACQUEMART  (alcohol). — A  black  precipitate  is 
obtained  on  heating  ordinary  alcohol  with  a 
solution  of  mercuric  nitrate  free  from  mercurous 
salt,  and  then  adding  ammonia. 

JACQUEMIN  (differentiation  of  silk,  wool,  and 
cotton). — The  textile  under  examination  is 
treated  with  a  tepid  solution  of  chromic  acid. 
Silk  and  woollen  fibres  are  coloured  yellow, 
whilst  cotton  fibres  remain  colourless. 

JACQUEMIN  (phenol). — A  blue  coloration  is  obtained 
on  treating  a  solution  of  phenol  with  a  little 
aniline  and  sodium  hypochlorite  solution. 
120 


REAGENTS   AND   REACTIONS. 

JACQUEMIN  (aniline). — A  dilute  aqueous  solution 
of  aniline  gives  a  red  coloration,  soon  changing 
to  yellow,  when  mixed  with  calcium  chloride 
solution  and  treated  with  a  dilute  solution  of 
ammonium  hydrosulphide. 

JAFFE  (quinuric  acid). — The  substance  when 
evaporated  to  dryness  on  the  water-bath  with 
hydrochloric  acid  and  potassium  chlorate  gives 
a  reddish  residue,  which  becomes  emerald-green 
when  moistened  with  ammonia  solution. 

JAFFE  (creatinine) . — The  precipitate  given  by  a 
saturated  solution  of  picric  acid  becomes 
yellowish-red  to  blood-red  on  the  addition  of 
sodium  hydroxide.  Creatine  does  not  give  this 
reaction. 

JAFFE  (indican  in  urine). — See  HAMMARSTEN. 

JAFFE  (urobilin). — Zinc  chloride  and  ammonia 
produce  a  red-green  fluorescence,  which  can  be 
removed  by  extraction  with  isobutyl  alcohol. 

JAGER  (DE)  (free  acids  in  gastric  juice). — The 
reagent  is  prepared  by  mixing  two  drops  of  ferric 
chloride  solution  with  0-5  grm.  of  sodium  sali- 
cylate  in  100  c.c.  of  water.  Two  c.c.  of  this 
reagent  are  diluted  with  80  per  cent,  of  water, 
and- treated  with  10  c.c.  of  the  gastric  juice.  In 
the  presence  of  hydrochloric  acid,  or  other 
mineral  acids,  the  yellowish-brown  colour  of 
the  reagent  changes  to  violet-blue,  and,  in  the 
presence  of  lactic  acid,  to  wine-red. 

JAKSCH  (hydrochloric  acid  in  gastric  juice). — An 
aqueous  solution  of  "  emerald-green  "  changes  its 
blue  colour  to  green  in  presence  of  even  dilute 
hydrochloric  acid. 

JAKSCH  (uric  acid). — The  reaction  is  essentially 
the  murexide  test,  with  the  difference  that 
chlorine  water  is  used  in  place  of  nitric  acid. 

JAKSCH  (dextrose). — This  is  the  well-known  reaction 
with  phenylhydrazine. 

JAKSCH  (melanin  and  melanogen  in  urine). — These 
121 


REAGENTS  AND   REACTIONS. 

two  substances  give  a  black  precipitate  with  a 
dilute  solution  of  ferric  chloride,  and  the  pre- 
cipitate is  soluble  in  potassium  hydroxide 
solution,  and  in  concentrated  acids. 

JAKSCH  (biliary  pigments  in  blood}. — The  serum 
separated  from  15  c.c.  of  blood  is  filtered,  and 
allowed  to  stand.  Normal  serum  is  of  a  clear 
yellow  colour,  and  becomes  milky ;  in  the  presence 
of  biliary  pigments  the  serum  is  green,  and,  on 
heating  to  60°  C.,  becomes  grass-green. 

JAQUEMIN  (urethan  in  urine). — A  large  quantity 
of  the  urine  is  extracted  with  ether,  and  the 
residue  from  the  ethereal  solution  is  taken  up 
with  water,  and  treated  with  potassium  hydroxide 
and  5  per  cent,  mercuric  chloride  solution,  until 
the  yellow  precipitate,  which  forms,  no  longer 
redissolves.  The  quantity  of  urethan  present 
is  proportional  to  the  amount  of  mercuric 
chloride  used. 

JAWOROWSKY  (albumin  in  urine}. — One  part  of 
ammonium  molybdate  and  4  parts  of  citric  acid 
are  dissolved  in  40  parts  of  water,  and  i  drop  of 
this  solution  is  added  to  4  c.c.  of  the  urine, 
which  ought  not  to  have  an  alkaline  reaction. 
In  the  presence  of  albumin  a  white  turbidity  is 
formed,  and  does  not  disappear  on  heating. 

JAWOROWSKY  (alkaloids). — The  reagent  consists 
of  a  solution  of  0-3  grm.  of  sodium  vanadate  in 
10  c.c.  of  hot  water,  mixed  with  a  solution  of 
0-3  grm.  of  copper  sulphate  in  10  c.c.  of  water, 
with  the  addition  of  a  little  acetic  acid,  to 
redissolve  the  resulting  precipitate.  One  drop 
of  this  reagent,  added  to  5  c.c.  of  the  solution  of 
the  alkaloid,  gives  a  precipitate,  especially  in 
the  case  of  concentrated  alkaloidal  solutions. 

JAWOROWSKY  (chloral). — (i)  When  resorcinol  is 
dissolved  in  a  dilute  aqueous  solution  of  chloral 
hydrate,  and  a  small  quantity  of  strong  sulphuric 
acid  is  added,  a  brown  ring  is  produced  at  the 

122 


REAGENTS  AND   REACTIONS. 

zone  of  contact,  and,  on  adding  ammonia 
solution  to  this  liquid,  the  supernatant  alkaline 
layer  becomes  reddish-yellow. 

(2)  On  heating  a  solution  of  chloral  hydrate 
with  a  little  phloroglucinol,  and  adding  a  little 
potassium  hydroxide,  an  intense  brown  colora- 
tion is  obtained  ;  when  the  liquid  is  shaken  with 
hydrochloric  acid  and  amyl  alcohol  the  latter 
takes  up  the  brown  coloration. 

JAWOROWSKY  (dextrose). — When  a  solution  of 
dextrose  is  rendered  alkaline,  and  boiled  with  a 
little  iodic  acid,  and  the  liquid  then  cooled  and 
acidified,  and  afterwards  treated  with  ammonia, 
a  brown  precipitate  of  nitrogen  iodide  is  obtained. 

JAWOROWSKY  (guaiacol). — One  drop  of  guaiacol 
reduces  an  ammoniacal  solution  of  silver  nitrate, 
especially  when  heated,  and  a  mixture  of 
guaiacol  with  ammoniacal  silver  nitrate  solution 
gives  a  red  coloration  after  a  short  time,  when 
treated  with  acetic  acid. 

JAWOROWSKY  (santonin). — On  shaking  a  solution 
of  0-02  grm.  of  santonin  in  2  c.c.  of  strong 
sulphuric  acid  with  a  i  per  cent,  solution  of 
cerium  sulphate,  acidified  with  sulphuric  acid, 
there  is  produced  a -cherry-red  coloration,  which 
becomes  turbid  on  cooling,  and,  when  diluted 
with  8  c.c.  of  water,  yields  a  violet  precipitate. 

JAWOROWSKY  (copper). — An  ammoniacal  solution 
of  phenol  gives  a  blue  coloration  within  an 
hour,  when  added  to  a  solution  containing 
copper. 

JOHANNSON  (alkaloids). — The  reagent  consists  of 
a  solution  of  i  grm.  of  ammonium  vanadate  in 
100  c.c.  of  strong  sulphuric  acid.  It  gives  the 
following  colorations  : — With  atropine,  reddish- 
yellow  ;  brucine,  blood-red  ;  codeine,  brownish- 
green  ;  coniine,  green ;  morphine,  brown ; 
papaverine,  violet ;  pilocarpine,  orange  ;  quini- 
dine,  blue-green  ;  quinine,  first  orange  and  then 
123 


REAGENTS  AND   REACTIONS. 

blue-green  ;  and  strychnine,  violet-blue,  chang- 
ing to  red. 

JOHNSON  (dextrose  in  urine). — The  urine  is  treated 
with  an  excess  of  mercuric  chloride,  and  filtered, 
and  the  excess  of  the  mercury  salt  removed  by 
means  of  ammonia.  On  the  addition  of  picric 
acid  and  potassium  hydroxide,  the  presence  of 
dextrose  is  indicated  by  the  formation  of  an 
intense  red  coloration,  due  to  potassium  isopur- 
purate. 

JOLLES  (albumin  in  urine}. — The  reagent  consists 
of  a  solution  of  i  grm.  of  mercuric  chloride, 
2  grms.  of  succinic  acid,  and  i  grm.  of  sodium 
chloride  in  50  c.c.  of  water.  Four  c.c.  of  the 
filtered  urine  are  introduced  into  two  test-tubes, 
and  acidified  with  i  c.c.  of  acetic  acid.  To  one 
portion  an  addition  of  4  c.c.  of  the  reagent  is 
made,  whilst  the  other  portion  is  diluted  with 
water.  The  tubes  are  shaken  and  compared, 
and  the  presence  of  albumin  is  shown  by  the 
formation  of  a  white  turbidity. 

JOLLES  (bromine  in  urine}. — Ten  c.c.  of  the  urine 
are  acidified  with  sulphuric  acid,  and  treated 
with  sufficient  potassium  permanganate  to  give 
a  permanent  pink  coloration.  Some  strips  of 
filter  paper  impregnated  with  a  o-i  per  cent, 
solution  of  />-dimethyl-phenylenediamine  are 
then  introduced  into  the  neck  of  the  flask,  and 
the  liquid  is  heated.  In  the  presence  of  bromine, 
the  strips  become  violet  in  the  middle,  and 
brown  at  the  edges. 

JOLLES  (histone  in  urine}. — From  50  to  100  c.c. 
of  the  urine  are  rendered  slightly  acid  with 
acetic  acid,  and  treated  with  barium  chloride, 
until  a  precipitate  no  longer  forms.  The  liquid 
is  then  filtered,  and  the  precipitate  dissolved  in 
10  c.c.  of  i  per  cent,  hydrochloric  acid.  After 
neutralisation  with  sodium  carbonate,  the  solu- 
tion is  filtered,  and  the  filtrate  is  treated,  first 
124 


REAGENTS  AND   REACTIONS. 

with  hydrochloric  acid,  and  then  with  ammonia. 
In  the  presence  of  histone  a  turbidity  is  obtained. 

JOLLES  (biliary  pigments  in  urine). — Fifty  c.c.  of 
the  urine  are  treated  with  a  few  drops  of  10  per 
cent,  hydrochloric  acid,  and  then  with  an  excess 
of  barium  chloride,  and  shaken  with  5  c.c.  of 
pure  chloroform.  After  standing  for  ten 
minutes,  the  chloroform  layer  is  separated,  and 
evaporated  on  the  water-bath  at  80°  C.  The 
residue  is  taken  up  with  water,  and  treated  with 
3  drops  of  nitric  acid  mixed  with  i  drop  of 
fuming  nitric  acid.  In  the  presence  of  biliary 
pigments,  the  characteristic  green  coloration 
with  blue  ring  is  obtained. 

JOLLES  (pyramidon  in  urine). — The  urine  is  treated 
with  i  c.c.  of  tincture  of  iodine,  diluted  with 
10  c.c.  of  water,  so  that  the  liquids  do  not  mix. 
In  the  presence  of  pyramidon  a  reddish-brown 
ring  is  produced  in  a  short  time. 

JOLLES  (mercury  in  urine). — One  hundred  c.c.  of 
the  urine  are  heated  with  2  grms  of  granular 
gold  in  the  presence  of  stannous  chloride.  The 
liquid  is  decanted,  and  the  amalgam,  obtained 
when  mercury  is  present,  is  washed  with  water, 
and  treated  with  an  equal  volume  of  a  freshly- 
made  saturated  solution  of  stannous  chloride. 
Traces  of  mercury  produce  a  distinct  turbidity. 

JORISSEN  (cinnamic  acid  in  benzoic  acid). — The 
benzoic  acid  is  shaken  in  a  closed  tube  with  a 
few  c.c.  of  a  3  per  cent,  saturated  aqueous 
solution  of  uranium  acetate,  and  the  tube  is 
exposed  to  direct  sunlight.  In  the  presence  of 
cinnamic  acid,  the  odour  of  benzaldehyde  will  be 
perceived. 

JORISSEN  (salicylic  acid). — The  solution  is  heated 
with  5  drops  of  a  10  per  cent,  solution  of  potas- 
sium nitrite,  followed  by  an  equal  quantity  of 
acetic  acid,  and  i  drop  of  a  10  per  cent, 
solution  of  copper  sulphate.  In  the  presence 
125 


REAGENTS  AND   REACTIONS. 

of  salicylic  acid,  a  blood-red  coloration  will  be 
produced. 

JORISSEN  (nitrous  acid}. — The  reagent  consists  of 
a  solution  of  o-oi  grm.  of  magenta  in  100  c.c.  of 
acetic  acid.  Nitrous  acid,  mixed  with  the 
reagent,  gives  a  violet  coloration,  changing  to 
violet,  then  to  yellow,  and  finally  disappearing. 

JORISSEN  (alkaloids  and  glucosides}. — One  grm. 
of  zinc  chloride  is  dissolved  in  30  c.c.  of  strong 
hydrochloric  acid  and  30  c.c.  of  water,  and  the 
liquid  under  examination  is  evaporated  to 
dryness  on  the  water-bath  with  this  reagent. 
The  following  colorations  are  produced : — 
Quinine,  green  ;  cubebine,  carmine-red ;  digi- 
taline,  brown ;  narceine,  olive-green ;  salicin, 
violet-red ;  santonin,  violet-blue ;  strychnine 
pink  ;  thebaine,  yellow  ;  and  veratrine,  red. 

JORISSEN  (apiol). — The  dilute  alcoholic  solution  is 
treated  with  chlorine  water  until  a  turbidity 
appears,  and  then,  on  the  addition  of  ammonia, 
gives  a  bright  red  coloration,  which  rapidly 
disappears. 

JORISSEN  (dulcine}. — From  i  to  2  grms.  of  freshly- 
precipitated  mercuric  oxide  is  dissolved  in  dilute 
nitric  acid,  and  the  solution  is  treated  with 
sodium  hydroxide  until  a  precipitate  begins  to 
form,  and  then  diluted  with  water  to  15  c.c. 
On  heating  5  c.c.  of  an  aqueous  solution  of 
dulcine  for  five  minutes  on  the  water-bath  with 
4  drops  of  the  reagent,  a  violet-blue  coloration 
is  obtained,  and  this  changes  to  violet  on  the 
addition  of  lead  peroxide. 

JORISSEN  (formaldehyde). — A  few  drops  of  formal- 
dehyde solution  are  placed  on  a  watch-glass 
beneath  a  glass  bell-jar,  whilst  beside  it  is  placed 
a  porcelain  crucible,  containing  a  few  crystals 
of  morphine  and  10  drops  of  strong  sulphuric 
acid.  The  formaldehyde  vapours  rapidly  turn 
the  acid  mixture  indigo-blue. 
126 


REAGENTS  AND   REACTIONS. 

JORISSEN  (fusel  oil}. — The  solution,  if  rich  in 
alcohol,  is  diluted  and  shaken  with  ether,  and  the 
ethereal  extract  evaporated.  On  treating  the 
residue  with  colourless  aniline  and  hydrochloric 
acid,  a  red  coloration  is  obtained. 

JORISSEN  (morphine). — On  heating  morphine  with 
strong  sulphuric  acid  and  with  a  crystal  of  ferrous 
sulphate,  and  adding  ammonia  solution  without 
mixing  the  two  liquids,  a  red  to  violet  zone 
is  obtained,  whilst  the  ammoniacal  liquid  is 
coloured  blue. 

JORISSEN  (ethyl  peroxide  in  ether). — The  reagent 
consists  of  0-4  grm.  of  vanadic  acid  dissolved  in 
4  c.c.  of  sulphuric  acid  and  diluted  with  water  to 
100  c.c.  On  shaking  2  c.c.  of  this  reagent  (which 
is  of  a  greenish-blue  colour)  with  10  c.c.  of  ether, 
a  pink  to  blood-red  coloration  is  obtained,  in  the 
presence  of  ethyl  peroxide. 

JUDD  (formaldehyde). — Ten  c.c.  of  the  liquid  under 
examination  are  treated  with  10  c.c.  of  5  per 
cent,  sodium  hydroxide  solution,  and  i  to  2  drops 
of  an  alcoholic  solution  of  phloroglucinol.  In  the 
presence  of  formaldehyde,  there  is  obtained,  after 
a  few  minutes,  a  pinkish-red  coloration,  changing 
to  brownish-yellow. 


K. 

KASTLE  (saccharin). — When  saccharin  is  heated 
with  phenol  and  strong  sulphuric  acid,  and  the 
mixture  is  diluted  with  a  little  water,  and 
rendered  alkaline  with  sodium  hydroxide,  a 
purple-red  or  pink  coloration  is  obtained. 
Sensitiveness  =  0-025  rngrm.  of  saccharin. 

KATAYAMA  (carbon  monoxide  in  blood). — The  blood 

is  diluted  with  50  volumes  of  water,  and  10  c.c.  of 

the  mixture  are  treated  with  0-2  c.c  of  yellow 

ammonium  sulphide,  and  with  0*3  c.c.  of  30  per 

127 


REAGENTS   AND   REACTIONS. 

cent,  acetic  acid,  so  as  to  have  a  slightly  acid 
liquid.  Normal  blood  becomes  greenish-grey, 
whilst  in  the  presence  of  carbon  monoxide,  a 
bright  red  coloration  is  obtained. 

KATHREIN  (biliary  pigments  in  urine). — Five  c.c.  of 
the  urine  are  treated  with  5  to  10  drops  of 
tincture  of  iodine.  In  the  presence  of  biliary 
pigments,  a  green  coloration  is  obtained,  whilst 
normal  urine  becomes  brownish-red. 

KELLER  (digitonine). — On  heating  o-oi  grm.  of 
digitonine  for  five  minutes  on  the  water-bath 
with  5  c.c.  of  strong  hydrochloric  acid,  the  solu- 
tion becomes  successively  yellow,  red,  and 
finally  violet-blue.  When  diluted,  after  cooling, 
with  20  c.c.  of  water,  a  liquid  with  a  reddish-blue 
fluorescence  is  obtained. 

KELLER  (ergotininey  cornutine). — The  alkaloid, 
which  is  insoluble  in  ether  acidified  with  hydro- 
chloric acid,  is  dissolved  in  acetic  acid,  and  the 
solution  is  made  to  fall  drop  by  drop  on  to  sul- 
phuric acid  containing  ferric  oxide.  A  blue  to 
violet  ring  is  produced. 

KENTMANN  (formaldehyde). — See  JORISSEN. 

KERNER  (quinine  in  urine). — The  urine  is  treated 
with  mercurous  nitrate  and  filtered,  and,  in  the 
presence  of  quinine,  the  filtrate  will  be  fluorescent. 
In  this  way,  it  is  possible,  by  the  use  of  Kerner's 
fluoroscope,  to  recognise  quinine  in  solutions  con- 
taining i  part  in  8,000,000. 

KERNER  (creatinine). — A  solution  of  creatinine 
acidified  with  a  mineral  acid  gives,  even  when 
very  dilute,  a  crystalline  precipitate  with  phos- 
photungstic  or  phosphomolybdic  acid. 

KERNER  (morphine}. — When  i  drop  of  a  solution  of 
morphine  is  treated  with  6  drops  of  ferric  chloride 
solution  (i  :  8)  and  3  drops  of  potassium  ferri- 
cyanide  solution  (i  :  100),  a  blue  coloration  and 
blue  precipitate  are  obtained. 

KILIANI-KELLER  (active -principles  of  digitalis}.— 
128 


REAGENTS  AND   REACTIONS. 

The  substance  is  dissolved  in  glacial  acetic  acid 
containing  ferric  sulphate,  and  the  solution  is 
dropped  on  to  sulphuric  acid  containing  ferric 
sulphate.  Digitoxine  and  digitonine  impart  a 
blue  colour  to  the  glacial  acetic  acid,  and 
digitaline  and  digitaligenine  a  violet-red  colour, 
whilst  digitoxigenine  produces  a  characteristic 
red  coloration,  with  pronounced  fluorescence. 

KIPPENBERGER  (colchicine) .  —  On  heating  an 
aqueous  solution  of  colchicine  with  excess  of  an 
alkaline  solution  of  hydroxylamine  hydrochloride, 
an  orange  coloration  is  obtained. 

KITASATO-SALKOWSKI  (indol). — One  c.c.  of  a 
0-2  per  cent,  solution  of  potassium  nitrite,  and  a 
little  sulphuric  acid,  are  added  to  10  c.c.  of  the 
culture  solution.  In  the  presence  of  indol  a  red 
coloration  is  produced. 

KLEINEMBERG  (stain  for  microscopy). — This  con- 
sists of  2-5  grms.  of  haematoxylin,  20  grms.  of 
crystalline  calcium  chloride  in  10  c.c.  of  water, 
3  grms.  of  alum  in  16  c.c.  of  water,  and  240  c.c. 
of  alcohol. 

KLETT  (indican  in  urine). — Ten  c.c.  of  the  urine  are 
treated  with  5  c.c.  of  officinal  hydrochloric  acid 
and  a  few  crystals  of  ammonium  persulphate, 
and  with  chloroform.  In  the  presence  of  indican, 
the  chloroform  becomes  blue. 

KLUNGE  (aloes). — An  aqueous  solution  of  aloes 
gives  a  blue  coloration  on  the  addition  of  copper 
sulphate  solution.  On  then  adding  alcohol  and 
sodium  chloride,  and  boiling  the  liquid,  the  colour 
changes  to  violet-red. 

KLUNGE  (berberine). — The  solution,  acidified  with 
hydrochloric  acid,  gives  a  red  coloration  on  the 
addition  of  chlorine  water. 

KNAPP  (glycogen). — Glycogen  precipitates  metallic 
mercury  from  a  hot  solution  of  mercury  cyanide. 
This  reduction  is  also  effected  by  dextrose  and 
by  creatine.  Hence,  Knapp  suggests  the  use  of 
R.R.  129  9 


REAGENTS   AND   REACTIONS. 

the  method  for  the  quantitative  estimation  of 
dextrose. 

KNOP  (urea). — See  HUFFNER. 

KNORR  (antipyrin).- — Antipyrin  gives  a  red  colora- 
tion, when  treated  with  ferric  chloride. 

ROBERT  (hydrocyanic  acid  in  blood). — The  normal 
brown  solution  of  methaemoglobin  is  turned  red 
by  hydrocyanic  acid,  whilst,  at  the  same  time,  the 
spectrum  of  methaemoglobin  gives  place  to  the 
mono-striated  spectrum  of  cyano-haemoglobin. 

ROBERT  (methczmoglobiri) . — The  addition  of  hydro- 
cyanic acid  imparts  a  red  coloration  to  a  neutral 
solution  of  methaemoglobin,  but  not  to  that  of 
haematin. 

ROBERT  (morphine  derivatives). — Sulphuric  acid  and 
formaldehyde  rapidly  turn  dionine  blue  ;  heroine 
becomes,  first  violet-red,  and  then  violet-blue  ; 
and  peronine  becomes  permanently  violet-red. 

ROCH  (stain  for  bacteriology}. — Five  c.c.  of  pure 
aniline  oil  are  mixed  with  100  c.c.  of  water,  and 
the  mixture  is  filtered  after  vigorous  shaking. 
To  the  clear  filtrate  is  added,  drop  by  drop,  a 
saturated  alcoholic  solution  of  methyl  violet, 
or,  better,  of  magenta  (20  grms.  in  100  to  150 
c.c,  of  alcohol),  until  a  slight  opalescence  is 
produced. 

ROHN  (glycerin). — When  glycerin  is  heated  with 
potassium  bisulphate  it  produces  acrolein,  which 
restores  the  pink  colour  to  a  solution  of  magenta 
decolorised  with  sulphur  dioxide  (Schiff  's  reagent) . 

ROSSEL  (hypoxanthin) . — On  treating  the  solution 
with  zinc  and  hydrochloric  acid,  and  then  making 
it  alkaline  with  sodium  hydroxide,  a  ruby-red 
coloration,  changing  to  brownish-red,  is  obtained. 

RRAEMER  (saffron). — Saffron  stamens  are  imme- 
diately coloured  blue,  when  treated  with 
sulphuric  acid. 

RRAL  (hydrogen  sulphide). — The  reagent  consists  of 
an  ammoniacal  solution  of  sodium  nitroprusside, 
130 


REAGENTS  AND   REACTIONS. 

which,  in  the  presence  of  hydrogen   sulphide, 
gives  a  violet  coloration. 

KRASSER  (proteins).  —  An  alcoholic  solution  of 
alloxan  gives  a  bright  red  coloration  on  contact 
with  solid  albumin. 

KRAUT  (alkaloids}.  —  See  DRAGENDORFF. 

KREHBIEL  (biliary  pigments  in  urine}.  —  This  is  a 
modification  of  Gmelin's  reaction,  and  consists 
in  the  use  of  hydrochloric  acid  and  calcium 
hypochlorite  as  the  oxidising  agent. 

KREIS  (cholesterol  and  phytosterol}  .  —  On  evapora- 
ting a  few  drops  of  an  ethereal  solution  of 
cholesterol  or  phytosterol  in  a  porcelain  crucible, 
and  treating  the  residue  with  2  drops  of  a  20  per 
cent,  alcoholic  solution  of  benzaldehyde  and  i 
drop  of  strong  sulphuric  acid,  the  residue 
becomes,  first  violet-red,  and  then  deep  violet. 
Picrotoxine,  which  behaves  in  a  similar  manner, 
finally  becomes  scarlet-red. 

KUBORNE  (cocaine}.  —  On  evaporating  a  small 
quantity  of  cocaine  to  dryness  with  i  c.c.  of 
65  per  cent,  nitric  acid,  on  the  water-bath,  a 
residue  is  obtained,  which,  while  cold,  remains 
colourless  after  the  addition  of  a  few  drops  of  a 
solution  of  potassium  hydroxide  in  amyl  alcohol. 
If,  however,  the  mixture  is  again  heated  on  the 
water-bath,  it  suddenly  develops  an  intense 
violet  coloration. 

KUHNE  (stain  for  bacteriology}.  —  This  consists  of 
1*5  grms.  of  methylene  blue,  10  c.c.  of  absolute 
alcohol,  and  100  c.c.  of  a  5  per  cent,  solution  of 
phenol.  It  keeps  well. 

KULZ  (biliary  pigments  in  urine}.  —  A  few  drops  of 
the  urine  are  evaporated  on  the  water-bath,  and 
treated  with  a  few  drops  of  a  solution  of  sugar, 
and  i  drop  of  sulphuric  acid.  In  the  presence 
of  biliary  acids,  the  mass,  when  heated,  becomes 
violet-red  at  the  edges. 
KuRT-Bo  AS  (adrenaline}  .  —  On  shaking  3  to  4  drops 


9-2 

COLLEGE 


.-VAJt   A 


REAGENTS  AND   REACTIONS. 

of  a  o-i  per  cent,  aqueous  solution  of  adrenaline 
with  6  to  8  c.c.  of  water  and  a  few  drops  of  a 
i  to  2  per  cent,  solution  of  mercuric  chloride,  a 
diffused  brown  coloration  is  produced  after  a  few 
minutes,  and  persists  for  several  days.  When 
the  liquid  is  heated  to  boiling,  it  immediately 
becomes  red. 


L. 

LABICHE  (cotton-seed  oil}. — Twenty  grms.  of  the  fat 
are  heated  with  the  same  quantity  of  lead  acetate 
solution  (50  grms.  in  100  c.c.),  and  the  mixture 
is  shaken  with  5  c.c.  of  ammonia  solution,  and 
maintained  at  35°  C.  In  the  presence  of  cotton- 
seed oil,  a  reddish-yellow  coloration  is  produced. 

LADENDORF  (hemoglobin). — Two  c.c.  of  the  liquid 
are  treated  with  2  drops  of  tincture  of  guaiacum, 
and  i  c.c.  of  oil  of  eucalyptus.  In  the  presence 
of  haemoglobin,  a  ring  is  produced,  which  is  blue 
below  and  violet  above. 

LAFON  (codeine). — One  grm.  of  ammonium  selenate 
is  dissolved  in  20  c.c.  of  pure  sulphuric  acid. 
This  reagent  produces  with  codeine  a  bright 
green  coloration,  which  rapidly  changes  to 
brownish-red. 

LAFON  (digitaline). — One  grm.  of  sodium  tellurate, 
or  selenate,  in  20  c.c.  of  sulphuric  acid,  gives  a 
greenish-blue  coloration,when  added  to  a  solution 
of  digitaline. 

LAFON-KELLER  (alkaloids). — The  reagent  consists 
of  strong  sulphuric  acid  containing  traces  of  iron 
oxide.  It  gives  a  blue  coloration  with  morphine, 
codeine,  and  heroine  ;  a  violet  coloration  with 
apomorphine,  digitaline  and  ergotine  ;  and  a 
red  coloration  with  thebaine,  narceine,  and 
laudanine. 

LAGORCHE  (cochineal). — This  turns  green  when 
treated  with  a  drop  of  uranium  acetate  solution. 
132 


REAGENTS  AND   REACTIONS. 

LAMAL  (morphine). — To  10  drops  of  the  solution 
under  examination  are  added  10  drops  of  a  solu  - 
tion  of  0-3  grm.  of  uranium  acetate  and  0-2  grm. 
of  sodium  acetate  in  10  c.c.  of  water,  and  the 
liquid  is  evaporated  to  dryness  in  a  porcelain 
basin.  In  the  presence  of  morphine  reddish- 
brown  or  purple-red  concentric  rings  are  pro- 
duced. 

LAMBERT  (phenols). — On  dissolving  a  little  iodo- 
form  (or  chloroform)  in  a  solution  of  a  phenol, 
and  adding  potassium  hydroxide,  the  following 
colorations  are  obtained : — Ordinary  phenol, 
resorcinol,  pyrogallol,  and  phloroglucinol,  red  ; 
salicylic  acid  and  orcinol,  reddish-violet ; 
guaiacol  and  thymol,  violet  ;  and  hydroquinone 
and  the  two  naphthols,  blue. 

LANDOLT  (phenol). — Bromine  water  gives  with 
phenol  a  white  precipitate  of  tribromophenol. 

LANGLEY  (alkaloids). — The  reaction  consists  in 
adding  to  a  salt  of  the  alkaloid,  potassium  nitrate 
and  sulphuric  acid,  and  finally  sodium  hydroxide. 
Chromatic  reactions  are  given  by  various  alka- 
loids, one  of  the  most  distinctive  being  that  of 
picrotoxine,  which  gives  a  deep  red  coloration. 

LASSAIGNE  (hydrocyanic  acid). — Sulphate  of  copper, 
in  the  presence  of  free  sulphur  dioxide,  produces 
a  turbidity  or  white  precipitate  in  solutions  of  a 
cyanide. 

LAUTH  (hydrogen  sulphide) .  —  Paraphenylenedia- 
mine,  in  slightly-acid  solution,  forms  Lauth's 
violet,  when  treated  with  ferric  chloride  in 
presence  of  hydrogen  sulphide.  If,  however,  the 
sulphate  of  ^-amino-dimethylaniline  is  used, 
methylene  blue  is  produced  (see  CARO-FISCHER). 

LAVE  (veratrine). — The  reagent  is  prepared  by 
mixing  4  drops  of  a  i  per  cent,  aqueous  solution 
of  furfural  with  i  c.c.  of  sulphuric  acid.  From 
4  to  5  drops  of  the  reagent  are  added  to  the  sub- 
stance under  examination  in  such  a  way  that  it 
133 


REAGENTS   AND   REACTIONS. 

remains  on  the  surface.  In  the  presence  of 
veratrine,  there  is  produced  a  pronounced  streak, 
which  is  first  green,  then  blue,  and  finally  violet. 
If  the  liquid  be  shaken,  it  becomes  deep  green, 
and,  after  a  short  time,  especially  when  heated, 
violet -blue. 

LEBLIN  (formaldehyde). — The  reagent  consists  of 
a  solution  of  resorcinol  in  sodium  hydroxide 
solution.  When  the  reagent  is  heated  for  half  a 
minute  with  form  aldehyde,  an  intense  red  colora- 
tion is  produced.  Proteins  interfere  with  the 
reaction. 

LECHINI  (blood  in  urine). — Ten  c.c.  of  the  urine  are 
treated  with  i  drop  of  acetic  acid  and  3  c.c. 
of  chloroform.  In  the  presence  of  blood,  the 
chloroform  layer  becomes  red. 

LEGAL  (acetone  in  urine). — The  distillate  from  the 
urine  is  treated  with  10  drops  of  a  10  per  cent, 
solution  of  sodium  nitroprusside,  and  then  with 
2  drops  of  potassium  or  sodium  hydroxide 
solution.  In  the  presence  of  acetone,  an  intense 
red  coloration  is  produced.  The  reaction  is 
intensified  by  adding  a  few  drops  of  acetic  acid. 

LEGAL  (indol). — The  so'uton  is  treated  with 
sodium  nitroprusside  until  yellow,  and  on  now 
adding  a  few  drops  of  dilute  sodium  hydroxide 
solution,  it  produces  a  magnificent  violet  colora- 
tion, which  changes  to  green  on  the  addition  of 
acids. 

LEGER  (chrysophanic  acid  and  chrysarobine). — 
(i)  On  treating  a  trace  of  chrysophanic  acid 
with  i  c.c.  of  strong  sulphuric  acid,  a  strawberry- 
red  coloration  is  obtained.  Chrysarobine,  under 
the  same  conditions,  gives  an  orange  coloration. 
(2)  When  chrysophanic  acid  is  ground  up 
with  alcohol,  and  then  treated  with  20  c.c.  of 
water  containing  5  drops  of  sodium  hydroxide 
solution  (35°  Be.),  it  immediately  dissolves,  and 
gives  a  strawberry-red  coloration.  Chrysarobine, 
134 


REAGENTS  AND   REACTIONS. 

under  the  same  conditions,  dissolves  slowly  and 
gives  a  pale  rose  coloration. 

LEGER  (a-  and  /3-naphthol) . — To  10  c.c.  of  a  cold 
saturated  solution  of  naphthol  are  added  2  drops 
of  sodium  hypobromite  solution.  In  the  presence 
of  a-naphthol,  the  liquid  becomes  deep  red, 
whilst  /2-naphthol  gives  a  yellow  coloration, 
which  changes  to  green,  and  then  to  yellow. 

LEHMANN  (dextrose). — On  treating  an  alcoholic 
solution  of  dextrose  with  alcoholic  potassium 
hydroxide  solution,  and  then  with  copper  sulphate 
solution,  and  heating  the  liquid,  cuprous  oxide 
separates. 

LEISMER  (dextrose  in  urine). — Two  c.c.  of  the  urine 
are  boiled  with  2  c.c.  of  sodium  hydroxide 
solution,  and  5  c.c.  of  a  o-i  per  cent,  solution  of 
safranine.  In  the  presence  of  dextrose,  the 
liquid  is  decolorised. 

LE-NOBLE  (acetone  in  urine). — See  LEGAL. 

LE-NOBLE  (biliary  pigments). — A  dichroic  spectrum 
is  obtained  on  treating  the  solution  with  zinc 
chloride  and  tincture  of  iodine. 

LENZ  (pilocarpine) . — On  treating  pilocarpine  hydro- 
chloride  with  mercurous  chloride,  reduction  takes 
place,  with  the  formation  of  a  black  coloration. 
Darkening  of  the  liquid,  though  less  intense,  also 
occurs  with  cocaine  hydrochloride  (Schell),  and 
with  stovaine  and  alipine  (Zernick) . 

LEPAGE  (alkaloids). — The  reagent  is  similar  to  that 
of  Marme. 

LETHEBY  (aniline). — A  blue  coloration  is  obtained 
on  heating  aniline  to  50°  C.  with  manganese 
dioxide  and  dilute  sulphuric  acid. 

LEX  (phenol). — On  treating  an  aqueous  solution  of 
phenol  with  an  alkali  nitrite  and  sulphuric  acid, 
and  then  adding  sodium  hydroxide,  a  brown 
coloration  is  obtained ;  and  on  then  adding 
calcium  hypochlorite,  the  colour  changes  to 
blue. 

135 


REAGENTS  AND   REACTIONS. 

LEWIN  (sesame  oil  in  olive  oil). — This  is  a  modifica- 
tion of  Baudouin's  reaction.  Two  c.c.  of  the  oil 
are  poured  on  to  0-5  grm.  of  powdered  sugar, 
and  i  c.c.  of  hydrochloric  acid  (sp.  gr.  —  1*18) 
is  poured  down  the  side  of  the  tube.  In  the 
presence  of  sesame  oil,  a  pink  zone  appears,  after 
about  five  minutes,  at  the  point  of  contact. 

LEYS  (saccharin). — Two  solutions  are  prepared, 
one  containing  2  c.c.  of  ferric  chloride  solution 
(30°  Be.)  in  100  c.c.  of  water,  and  the  other 
.  i  c.c.  of  hydrogen  peroxide  (10  volumes)  in 
200  c.c.  of  water.  On  treating  5  c.c.  of  a  sac- 
charin solution  with  2  drops  of  the  ferric  chloride 
solution,  and  2  c.c.  of  the  hydrogen  peroxide 
solution,  a  violet  coloration  is  produced  after 
thirty  to  forty-five  minutes. 

LIEBEN  (acetone  in  urine). — The  distillat^  f  rom 
urine  containing  acetone  forms  iodoform,  on 
the  addition  of  potassium  hydroxide  and  iodine. 

LIEBERMANN  (cholesterol). — On  treating  a  solution 
of  cholesterol  in  acetic  anhydride  with  strong 
sulphuric  acid,  a  pink  coloration,  changing 
rapidly  to  intense  blue  and  to  green,  is  obtained. 
The  reaction  is  rendered  more  sensitive  by  using 
chloroform  in  place  of  acetic  anhydride.  Sen- 
sitiveness —  i  :  20,000. 

LIEBERMANN  (phenols). — On  treating  phenols  with 
a  small  quantity  of  a  reagent  consisting  oi: 
5  parts  of  potassium  nitrate  in  100  c.c.  of  sul- 
phuric acid,  various  colorations  are  produced, 
which  change  to  blue  on  neutralising  the  liquid 
with  potassium  hydroxide. 

LIEBERMANN  (ethyl  sulphide  in  urine). — Eight  grms. 
of  potassium  nitrite  are  dissolved  in  100  grms.  of 
strong  sulphuric  acid  diluted  with  6  to  7  c.c.  of 
water,  and  the  solution  is  filtered  through  glass 
wool.  In  the  presence  of  ethyl  sulphide,  this 
reagent  produces  a  fugitive  green  coloration. 

LIEBERMANN  (proteins). — The  substance  is  washed 
136 


REAGENTS   AND   REA 

with  alcohol,  and  treated  with  concentrated 
hydrochloric  acid.  In  the  presence  of  proteins, 
a  fine  violet-blue  coloration  is  obtained. 

LIEBIG  (hydrocyanic  acid] . — On  evaporating  hydro- 
cyanic acid  with  ammonium  sulphide,  a  residue 
is  left,  which  becomes  blood-red  on  the  addition 
of  ferric  chloride  previously  acidified  with 
hydrochloric  acid  (ferric  thiocyanate) . 

LIEBIG  (cystine). — When  cystine  is  boiled  with 
sodium  hydroxide  solution  containing  lead 
oxide,  a  black  coloration,  due  to  the  formation 
of  lead  sulphide,  is  obtained. 

LIEBIG  (urea). — Urea  forms  a  white  precipitate 
with  mercurous  nitrate.  The  reaction  is 
quantitative. 

LINDO  (nitrates  and  nitrites). — On  mixing  0*5  c.c.  of 
a  solution  of  either  of  these  salts  with  i  drop  of 
hydrochloric  acid  (15  per  cent.),  i  drop  of 
a  10  per  cent,  solution  of  resorcinol,  and  2  c.c.  of 
pure  sulphuric  acid,  a  purple-red  coloration  is 
obtained. 

LINDO  (saccharin). — The  residue  left  on  evaporating 
a  solution  of  saccharin  in  nitric  acid  gives,  when 
treated  with  a  50  per  cent,  alcoholic  solution  of 
potassium  hydroxide,  a  coloration,  which  is  first 
blue,  then  violet,  and  finally  purple-red. 

LOFFLER  (stain  for  bacteriology}. — This  consists  of 
30  c.c.  of  a  saturated  alcoholic  solution  of  methy- 
lene  blue,  and  100  c.c.  of  a  solution  of  potassium 
hydroxide  (i  :  10,000). 

LONGI  (nitric  acid). — The  reagent  is  an  aqueous 
solution  of  paratoluidine  sulphate.  On  adding 
a  few  drops  thereof  to  the  liquid  under  examina- 
tion, and  then  an  equal  volume  of  strong  sul- 
phuric acid,  there  is  produced,  in  the  presence  of 
nitric  acid,  a  red  zone,  which  changes  to  dark 
yellow. 

LOUBIOU  (indican  in  urine). — Two  c.c.  of  the  urine 
are  treated  with  an  equal  volume  of  chloroform, 
137 


REAGENTS  AND   REACTIONS. 

and  with  i  c.c.  of  5  to  10  per  cent,  hydrogen 
peroxide.  Then,  after  the  addition  of  2  drops 
of  strong  hydrochloric  acid,  the  liquid  is  slightly 
heated,  and  shaken.  In  the  presence  of  indican, 
the  chloroform  becomes  blue. 

LOWE  (dextrose). — A  solution  of  copper  sulphate 
(16  grms.  in  150  c.c.  of  water)  is  mixed  with 
glycerin  (sp.  gr.  1-8),  and  sodium  hydroxide  is 
added,  until  the  precipitate  first  formed  is 
redissolved.  Dextrose  gives  the  usual  red 
precipitate  on  heating. 

LOWE  (natural  and  artificial  silk). — The  preceding 
reagent  dissolves  natural,  but  not  artificial 
silk. 

LOWENTHAL  (dextrose  in  urine}. — The  reagent 
consists  of  60  grms.  of  tartaric  acid,  240  grms. 
of  potassium  carbonate,  and  5  grms.  of  crystalline 
ferric  chloride,  dissolved  in  500  c.c.  of  water  and 
filtered.  If  urine  gives  a  brown  precipitate  when 
boiled  with  this  reagent,  dextrose  is  present. 

LUCHINI  (alkaloids). — The  reagent  consists  of  a 
hot  recently-prepared  solution  of  potassium 
bichromate  in  strong  sulphuric  acid.  Charac- 
teristic colorations  are  produced  when  different 
alkaloids  are  treated  with  this  reagent. 

LUCRE  (hippuric  acid). — On  heating  hippuric  acid 
with  strong  nitric  acid,  and  then  evaporating  the 
liquid  to  dryness,  a  residue  emitting  a  strong 
odour  of  nitrobenzene  is  left. 

LUGOL  (albumin  in  urine). — One  part  of  Lugol's 
reagent  (i  of  iodine  and  2  of  potassium  iodide  in 
20  parts  of  water),  when  mixed  with  4  parts  of 
water  and  5  parts  of  acetic  acid,  forms  a  solution 
which  precipitates  albumin. 

LUNGE-WOLFF  (nitrous  acid). — See  GRIESS. 

LUSTGARTEN  (iodoform) . — A  solution  of  o-i  grm. 
of  resorcinol  in  5  c.c.  of  alcohol  is  treated  with  a 
fragment  of  metallic  sodium.  On  mixing  5  drops 
of  this  reagent  with  an  ethereal  solution  of 

138 


REAGENTS  AND   REACTIONS. 

iodoform,  and  heating  the  liquid  carefully  until 
the  ether  has  been  removed,  a  cherry-red  colora- 
tion is  produced. 

M. 

MABEN  (almond  oil). — Ten  drops  of  the  oil  are 
shaken  with  5  drops  of  a  saturated  solution  of 
zinc  chloride.  Almond  oil  gives  no  coloration, 
but  peach  or  apricot  oils  give  a  brownish-red 
coloration. 

MAcMuNN  (indican  in  urine). — Equal  parts  of  the 
urine  and  hydrochloric  acid  are  boiled  with 
2  drops  of  nitric  acid,  and  the  liquid  cooled,  and 
shaken  with  chloroform.  In  the  presence  of 
indican,  the  chloroform  assumes  a  violet  colour, 
and  shows  a  characteristic  spectrum  with  two 
absorption  bands. 

MAC  WILLIAM  (albumin  in  urine). — The  urine  under 
examination  is  shaken  for  a  few  minutes  with  a 
few  crystals  of  sulphosalicylic  acid.  In  the 
presence  of  albumin,  a  flocculent  precipitate  is 
obtained. 

MALAQUIN  (strychnine). — One  c.c.  of  the  solution 
is  mixed  with  i  c.c.  of  pure  hydrochloric  acid, 
and  treated  with  i  grm.  of  pure  zinc,  and  then, 
after  four  minutes,  it  is  rapidly  heated  to  boiling, 
and  cooled.  On  now  pouring  this  liquid  down 
the  sides  of  a  tube  containing  2  c.c.  of  pure  sul- 
phuric acid,  a  pink  coloration  is  obtained  at  the 
zone  of  contact,  and  rapidly  diffuses  into  all  the 
liquid,  when  strychnine  is  present. 

MALERBA  (acetone). — A  solution  of  dime  thy  Ipara- 
phenylenediamine  gives  a  red  coloration  with 
acetone. 

MANCHOT-KAMPESCHULTE  (ozone). — When  a  piece 

of  silver  foil  is  heated  to  about  400°  C.,  and 

brought  into  contact  with  ozone,  bright  bluish 

spots  with  violet  edges  soon  appear.    In  the  cold, 

139 


REAGENTS  AND   REACTIONS. 

this  reaction  does  not  take  place  if  the  silver  is 
pure  ;  but  if  the  silver  foil  is  first  rubbed  with 
emery  paper,  the  reaction  takes  place,  even  in  the 
cold.  This  reaction  is  not  given  by  hydrogen 
peroxide. 

MANDELIN  (alkaloids). — The  reagent  consists  of  a 
solution  of  i  grm.  of  ammonium  vanadate  in 
200  grms.  of  strong  sulphuric  acid.  With  this 
reagent  morphine  gives  a  violet,  and  then  bright 
blue  coloration  ;  codeine  and  colchicine,  green- 
blue  ;  narceine,  violet  and  then  orange ; 
strychnine,  violet-blue  and  then  red  ;  and  colo- 
cynthine  and  veratrine,  a  blood-red  coloration. 

MANGINI  (alkaloids). — The  reagent  is  prepared  by 
heating  3  grms.  of  potassium  iodide  and  16  grms. 
of  bismuth  iodide  with  3  grms.  of  hydrochloric 
acid.  It  gives  brown  precipitates  with  solutions 
of  alkaloidal  salts. 

MANKIEWICZ  (albumin  in  urine). — See  MAC- 
WILLIAM. 

MANN  (citric  acid). — When  citric  acid  is  heated 
with  its  own  weight  of  glycerin  until  the  mixture 
has  solidified,  the  mass  dissolved  in  hot  ammonia 
solution,  and  the  solution  concentrated  by 
exposure  to  the  air  for  a  few  hours,  there  is  pro- 
duced a  green  coloration,  which  becomes  more 
intense  on  the  addition  of  hydrogen  peroxide. 

MANSEAU  (nitrous  acid). — A  few  c.c.  of  the  liquid 
under  examination  are  mixed  with  2  to  5  c.c. 
of  a  5  per  cent,  solution  of  antipyrin,  and  then 
shaken  with  I  drop  of  sulphuric  acid.  In  the 
presence  of  nitrous  acid,  a  green  or  bluish-green 
coloration  is  produced. 

MARECHAL  (biliary  pigments  in  urine). — On  treating 
acid  or  neutral  urine  containing  biliary  pigments 
with  3  drops  of  tincture  of  iodine,  an  emerald- 
green  coloration  is  produced  (see  SMITH). 

MARME  (alkaloids). — The  reagent  is  prepared  by 
saturating  a  boiling  concentrated  solution   of 
140 


REAGENTS  AND   REACTIONS. 

potassium  iodide  (4  parts  in  12  parts  of  water) 
with  cadmium  iodide,  and  then  adding  an  equal 
volume  of  a  cold  saturated  solution  of  potassium 
iodide.  This  reagent  gives  yellowish-white  pre- 
cipitates with  the  salts  of  alkaloids. 

MARQUE  (sparteine). — When  sparteine  sulphate  is 
slightly  heated  in  a  crucible  with  a  third  of  its 
weight  of  chromic  acid,  the  mass  becomes  green, 
and  emits  an  odour  of  cicutine. 

MARQUIS  (alkaloids). — The  reagent  consists  of  a 
mixture  of  3  c.c.  of  strong  sulphuric  acid  with 
3  drops  of  35  per  cent,  formaldehyde  solution. 
Treated  with  this  reagent,  morphine  gives  a 
purple-red  coloration,  changing  to  violet  and  then 
to  blue  ;  the  same  colorations  are  also  produced 
by  codeine,  dionine,  and  heroine. 

MARSH  (arsenic). — This  is  the  well-known  test, 
depending  on  the  formation  of  arsine,  when 
arsenical  compounds  are  treated  with  nascent 
hydrogen,  and  the  decomposition  of  the  arsine 
by  heat  with  liberation  of  free  arsenic,  which  is 
deposited  as  a  ring  or  as  dark  spots  within  a 
tube. 

MATHIEU-PLESSY  (sugars). — A  fused  mixture  of 
54  grms.  of  ammonium  nitrate,  34  grms.  of  lead 
nitrate,  and  21  grms.  of  lead  hydroxide  gives  a 
red  coloration  with  dextrose,  and  a  greenish- 
brown  coloration  with  sucrose. 

MAUMENE  (dextrose). — On  heating  a  solution  of 
dextrose  with  a  38  per  cent,  solution  of  stannous 
chloride,  it  darkens,  and  yields  a  black  pre- 
cipitate. 

MAYER  (alkaloids}. — The  reagent  is  prepared  by 
dissolving  13-55  grms.  of  mercuric  chloride,  and 
50  grms.  of  potassium  iodide  in  a  litre  of  water. 
It  gives  white  precipitates  with  most  alkaloids 
in  faintly-acid  solution. 

MECKE  (alkaloids}. — The  reagent  consists  of  a 
solution  of  selenious  acid  in  strong  sulphuric 
141 


REAGENTS  AND   REACTIONS. 

acid  (i :  200) .  It  gives  various  coloured  reactions 
with  alkaloids,  such  as,  for  example  : — Codeine, 
blue  coloration  in  the  cold,  changing  to  emerald- 
green  ;  morphine,  blue  and  then  olive-green  ; 
narceine,  greenish-yellow ;  and  papaverine,  dark 
blue  and  then  violet ;  saponine  from  guaiacum 
bark  gives  a  magnificent  violet  coloration  in 
this  test. 

MEHU  (albumin  in  urine). — A  mixture  of  i  part 
of  phenol,  i  of  acetic  acid,  2  of  alcohol,  and  2  of 
the  urine,  which  has  been  previously  treated 
with  nitric  acid,  gives  a  precipitate,  when 
albumin  is  present. 

MELZER  (coniine  and  nicotine). — An  alcoholic 
solution  of  coniine  gives  a  brown  coloration, 
when  treated  with  a  few  drops  of  carbon  bisul- 
phide, and  then,  after  a  few  seconds,  with  a 
solution  of  copper  sulphate  (1:200).  Nicotine, 
under  the  same  conditions,  gives  a  yellow  colora- 
tion. On  dissolving  i  drop  of  nicotine  in  2  to 
3  c.c.  of  epichlorhydrin,  and  heating  the  solution 
to  boiling,  there  is  produced  a  pronounced  red 
coloration. 

MELZER  (phenol). — When  i  c.c.  of  an  aqueous  solu- 
tion of  phenol  is  heated  with  2  c.c.  of  strong 
sulphuric  acid  and  a  few  drops  of  benzaldehyde, 
a  brownish-yellow  mass  is  obtained,  which  be- 
comes deep  red  on  heating.  After  cooling,  10  c.c. 
of  water  are  added,  and  the  liquid  rendered 
alkaline  with  20  per  cent,  potassium  hydroxide 
solution.  A  fine  bluish-violet  coloration  is 
produced,  the  colouring  matter  being  soluble  in 
ether. 

MELZER  (picrotoxine,  cholesterol,  phylosterol) . — On 
treating  a  trace  of  the  substance  with  i  drop  of  a 
20  per  cent,  solution  of  benzaldehyde,  and  then 
with  a  drop  of  strong  sulphuric  acid,  a  violet-red 
coloration  is  produced. 

MELZER  (alkaloids). — The  alkaloid  is  treated  in  a 
142 


REAGENTS   AND   REACTIONS. 

porcelain  crucible,  first  with  a  drop  of  a  20  per 
cent,  solution  of  benzaldehyde  in  absolute  alcohol, 
and  then  with  a  drop  of  sulphuric  acid.  Digi- 
taline  gives  a  brownish-yellow  coloration  ;  vera- 
trine,  red  ;  codeine,  yellow  or  blood-red  ;  the- 
baine,  brown  spots  ;  and  morphine,  red  streaks. 

MERCH  (alcohol}. — The  reagent  is  prepared  by  dis- 
solving molybdic  acid  in  strong  hot  sulphuric 
acid,  and  this  solution  is  added  to  the  liquid  under 
examination,  which  has  been  heated  to  60°  C.  In 
the  presence  of  alcohol,  a  blue  ring  is  formed  at 
the  zone  of  contact. 

MESSINGER  (acetone  in  urine}. — The  distillate  from 
urine  containing  acetone  yields  iodoform,  when 
treated  with  potassium  hydroxide  and  iodine. 

METZGER  (cocaine} . — On  treating  an  aqueous  solu- 
tion of  a  salt  of  cocaine  with  potassium  chromate, 
and  then  acidifying  the  liquid  with  hydrochloric 
acid,  an  orange-yellow  precipitate  is  produced. 

MEYER  (thiophen). — Thiophen  gives  a  blue  colora- 
tion, when  treated  with  a  solution  of  isatin  in 
strong  sulphuric  acid. 

MILLIAU  (cotton-seed  oil  in  olive  oil} . — The  free  fatty 
acids  are  separated  from  the  oil  under  examina- 
tion, and  dissolved  in  20  c.c.  of  90  per  cent, 
alcohol,  and  the  solution  is  treated  with  2  c.c.  of 
a  3  per  cent,  alcoholic  solution  of  silver  nitrate. 
On  heating  the  mixture  to  90°  C.,  a  brown  colora- 
tion indicates  the  presence  of  cotton-seed  oil. 

MILLON  (phenols). — One  part  of  mercury  is  dis- 
solved in  i  part  of  nitric  acid  (sp.  gr.  1-40),  with 
the  aid  of  gentle  heat,  and  the  solution  is  diluted 
with  2  parts  of  water.  Should  the  reagent 
become  weak  after  keeping,  a  few  crystals  of 
potassium  nitrate  are  added.  This  reagent  gives 
a  red  coloration  and  red  precipitate  with  various 
phenols.  Substances  with  a  phenolic  function, 
such  as  certain  proteins,  also  behave  in  the  same 
way. 

143 


REAGENTS  AND   REACTIONS. 

MINOWIC  (picrotoxine}. — On  treating  a  few  drops  of 
a  solution  of  picrotoxine  with  2  drops  of  sul- 
phuric acid,  and  then,  after  a  few  minutes,  adding 
i  drop  of  a  20  per  cent,  solution  of  anisic  aldehyde 
in  absolute  alcohol,  a  saffron-yellow  coloration  is 
obtained  when  the  sulphuric  acid  is  added,  whilst 
the  addition  of  the  aldehyde  produces  an  indigo- 
violet  zone,  the  colour  of  which  changes  to  blue. 

MITCHELL  (formaldehyde). — (i)  On  treating  a  solu- 
tion containing  formaldehyde  with  I  c.c.  of  nitric 
acid  and  i  c.c.  of  potassium  bichromate  solution, 
a  blue  coloration  is  obtained. 

(2)  Nessler's  reagent  gives  a  precipitate  with 
solutions  of  formaldehyde. 

MITCHELL  (fruit  acids,  vanadates): — On  heating  a 
i  per  cent,  solution  of  ammonium  metavanadate 
with  oxalic  acid,  the  vanadium  compound  is 
reduced,  and  a  blue  solution  obtained.  Tartaric 
and  citric  acids,  and,  to  a  less  extent,  malic  acid, 
cause  a  similar  reduction.  Conversely,  the  test 
may  be  used  for  distinguishing  between  chro- 
mates  and  vanadates. 

MOER  (VAN)  (cytiscine). — When  treated  with  a 
mixture  of  5  per  cent,  ferric  chloride  solution 
and  0-05  per  cent,  hydrogen  peroxide  solution, 
cytiscine  gives  a  red  coloration,  changing  to  blue. 

MOERCK  (vanillin). — On  treating  a  solution  of 
vanillin  with  a  few  drops  of  bromine  water  until 
the  odour  of  bromine  is  perceptible,  and  then 
adding  a  few  drops  of  a  freshly-prepared  solution 
of  ferrous  sulphate,  a  green  coloration  is  pro- 
duced. 

MOHLER  (tartaric  acid}. — One  grm.  of  resorcinol  is 
dissolved  in  i-oo  grms.  of  sulphuric  acid 
(sp.  gr.  1-84),  and  i  c.c.  of  the  solution  is  heated 
to  125°  to  130°  C.  with  the  substance  under 
examination.  In  the  presence  of  tartaric  acid,  a 
red  coloration  is  obtained. 

MOHR  (hydrochloric  acid  in  gastric  juice] . — A  5  per 
144 


REAGENTS   AND   REACTIONS. 

cent,  solution  of  iron  acetate  is  diluted  until  it  is 
of  only  a  light  yellow  colour,  and  is  then  treated 
with  a  few  drops  of  a  10  per  cent,  solution  of 
potassium  thiocyanate,  which  ought  not  to 
change  the  colour.  On  adding  to  this  reagent 
the  nitrate  from  the  gastric  juice,  an  intense 
blood-red  coloration  will  be  obtained,  in  the 
presence  of  free  hydrochloric  acid. 

MOLISCH  (cellulose). — A  15  to  20  per  cent,  alcoholic 
solution  of  thymol,  diluted,  filtered,  and  treated 
with  potassium  chloride,  gives  a  blue  coloration 
on  contact  with  cellulose. 

MOLISCH  (sugars). — One  c.c.  of  the  liquid  under 
examination  is  treated  with  2  drops  of  a  15  to  20 
per  cent,  alcoholic  solution  of  a-naphthol,  and 
then  with  i  c.c.  of  sulphuric  acid,  and  Ithe 
mixture  again  shaken.  In  the  presence  of 
sugars,  a  violet  coloration  is  produced,  and  on 
adding  water  there  is  formed  a  violet-blue  pre- 
cipitate, which  dissolves  in  alcohol  and  ether, 
yielding  a  slightly  yellow  solution. 

MOLLE  (veronal). — A  saturated  aqueous  solution  of 
veronal,  when  treated  with  nitric  acid  and  a  little 
of  Millon's  reagent,  gives  a  gelatinous  white 
precipitate  soluble  in  excess  of  the  reagent. 

MONPURGO  (dulcine). — The  dulcine  is  extracted 
with  alcohol  and  ether,  and  the  residue  from  the 
extract  is  heated  with  a  mixture  of  2  drops  of 
pure  phenol  and  2  drops  of  strong  sulphuric  acid. 
The  liquid,  which  will  be  of  a  bright  red  colour, 
is  cooled,  diluted  with  water,  and  cautiously 
added  to  a  solution  of  ammonia  or  sodium 
hydroxide.  A  characteristic  violet  or  blue 
coloration  will  be  produced  at  the  zone  of 
contact. 

MOORE  (dextrose). — When  a  solution  of  dextrose  is 
heated  with  potassium  hydroxide  it  gives  a  yellow 
and  then  a  brown  coloration,  and  on  adding 
excess  of  an  acid  an  odour  of  caramel  is  produced. 
R.R.  145  I0 


REAGENTS  AND   REACTIONS. 

MULDER  (proteins). — Proteins  treated  with  strong 
nitric  acid  give  a  lemon-yellow  coloration,  due  to 
the  formation  of  xantho-protein.  The  colour  is 
changed  to  orange  by  alkalies. 

MULDER  (dextrose). — When  a  solution  containing 
dextrose  is  heated  with  a  solution  of  indigo 
sulphate,  which  has  been  neutralised  with  sodium 
hydroxide,  the  indigo  dyestuff  is  reduced,  and 
changed  to  green,  and  then  to  red  and  yellow, 
but  on  exposure  to  the  air  regains  its  blue 
colour. 

MULLER  (cystine  in  urine}. — When  cystine,  ob- 
tained from  the  sediments  of  urine,  is  dissolved 
in  hot  potassium  hydroxide  solution,  and  the 
solution  diluted  with  water,  and  treated  with 
Stdium  nitroprusside,  a  purple-violet  coloration 
is  produced. 

MULLIKEN-SCUDDER  (methyl  alcohol}. — A  spiral  of 
copper  wire  is  immersed  several  times  in  the 
methyl  alcohol,  and  to  the  solution  thus  oxidised 
is  added  a  5  per  cent,  aqueous  solution  of 
resorcinol,  and  the  mixture  is  poured  on  to  the 
surface  of  strong  sulphuric  acid.  At  the  zone 
of  contact  of  the  two  liquids  a  red  ring  appears, 
and,  after  standing  for  some  time,  a  purple-red 
flocculent  precipitate  separates. 

Mussi  (benzanilide) . — On  treating  a  liquid  con- 
taining benzanilide  with  a  fewr  drops  of 
sulphuric  acid,  cooling  the  mixture,  and  shaking 
it  with  ether,  then  adding  a  few  drops  of  potas- 
sium bichromate  solution,  and  repeating  the 
shaking,  the  upper  layer  will  be  ultramarine-blue 
and  the  lower  emerald-green. 

MYLIUS  (biliary  acids  in  urine}. — One  drop  of  a 
solution  of  furfural  and  i  c.c.  of  strong  sulphuric 
acid  are  added  to  an  alcoholic  solution  of  the 
supposed  biliary  acids,  and  the  mixture  is  cooled. 
In  the  presence  of  biliary  acids,  there  is  formed 
red  coloration,  which  does  not  disappear  for  a 
146 


REAGENTS   AND   REACTIONS. 

considerable  time,  but  changes  to  violet-blue 
after  twenty-four  hours  (see  PETTENKOFER, 
UDRANSKY). 

N. 

NEEBAUER  (biliary  acids  in  urine). — A  few  drops  of 
the  urine  are  evaporated  on  the  water-bath,  and 
the  residue  is  treated  with  i  drop  of  a  solution  of 
sugar  (i :  50) ,  and  then  with  a  drop  of  strong 
sulphuric  acid,  and  again  heated  on  the  water- 
bath.  In  the  presence  of  biliary  acids,  a  violet- 
red  ring  is  formed  on  the  sides  of  the  crucible. 

NEEBAUER  (chloroform  in  urine). — A  current  of  air 
is  passed  through  the  urine,  and  then  through  a 
tube,  heated  to  redness,  into  a  solution  of  silver 
nitrate.  If  the  urine  contained  chloroform,  a 
precipitate  of  silver  chloride  will  be  obtained. 

NENCKI  (indol). — Indol  gives  with  nitric  acid  con- 
taining nitrogen  oxides  a  pronounced  red  colora- 
tion, and,  in  the  case  of  concentrated  solutions, 
may  also  yield  a  red  precipitate. 

NESSLER  (ammonia). — Six  grms.  of  mercuric 
chloride  are  dissolved  in  50  c.c.  of  water,  and  the 
solution  mixed  with  a  solution  of  7-4  grms.  of 
potassium  iodide  in  50  c.c.  of  water.  The  liquid  is 
cooled,  and  decanted  from  the  precipitate,  which 
is  washed  three  times  by  decantation  with  20  c.c. 
of  water.  It  is  then  treated  with  5  grms.  of  potas- 
sium iodide  and  a  little  water,  which  dissolve  the 
mercuric  iodide.  The  solution  thus  obtained  is 
treated  with  a  solution  of  20  grms.  of  sodium 
hydroxide  in  a  little  water,  and,  after  cooling, 
the  liquid  is  diluted  with  water  to  100  c.c.  This 
reagent  gives  with  ammonia  or  ammonium  salts 
an  intense  yellow  coloration,  whilst  with  large 
quantities  of  ammonia  it  gives  a  brown  pre- 
cipitate. 

NESSLER   (aldehydes). — The  reagent,  prepared  as 

147  10—2 


REAGENTS  AND   REACTIONS. 

described  above,  or,  better,  a  solution  of  mer- 
curic iodide  in  potassium  iodide  solution  to  which 
baryta  water  has  been  added,  may  be  used  for 
the  detection  of  aldehydes.  With  these  it  forms 
a  yellowish-white  or  brownish-red  to  black 
precipitate,  according  to  the  quantity  of  aldehyde 
present. 

NEUBAUER-VOGEL  (dextrose). — This  is  identical 
with  Fehling's  reagent. 

NEUBERG  (formaldehyde). — The  reagent  consists  of 
an  aqueous  solution  of  the  chloride  of  p-dihydro- 
diphenylazine,  which  gives  a  yellow  coloration 
when  heated  with  formaldehyde. 

NEUHAUS  (santonine  in  urine) . — The  urine  becomes 
violet-red  when  treated  with  Fehling's  solution, 
and,  on  the  addition  of  acetic  acid,  the  colour 
changes  to  bright  green. 

NICKEL  (phloridzine). — On  boiling  the  substance 
with  a  large  quantity  of  potassium  nitrite  and 
zinc  sulphate,  a  violet-blue  coloration  is  obtained. 

NICKEL  {vanillin}. — Vanillin  gives  a  violet  colora- 
tion, when  heated  with  potassium  nitrite  and 
mercuric  chloride. 

NICKLES  (peach-kernel  oil  in  almond  oil). — Twelve 
grms.  of  the  oil  are  vigorously  shaken  with 
1-5  grms.  of  powdered  slaked  lime,  and  the 
mixture  is  heated  for  fifteen  minutes  on  the 
water-bath,  and  filtered  while  hot.  The  filtrate 
remains  clear  after  cooling  in  the  case  of  pure 
almond  oil,  but  becomes  opalescent  if  peach- 
kernel  or  apricot-kernel  oils  are  present. 

NICOLLE  (stain  for  microscopy). — The  solution  con- 
sists of  100  c.c.  of  a  saturated  solution  of  thionine 
in  50  per  cent,  alcohol,  with  10  c.c.  of  a  i  per  cent, 
solution  of  phenol. 

NicoLLE-MoRAN  (stainfor  bacteriology). — Five  grms. 

of  pure  tannin  are  mixed  with  20  c.c.  of  water, 

10  c.c.  of  a  cold  saturated  solution  of  ferrous 

sulphate,  and  2  c.c.  of  a  saturated  solution  of 

148 


REAGENTS  AND   REACTIONS. 

magenta  in  absolute  alcohol.  The  liquid  is 
filtered  after  two  to  three  days. 
NYLANDER  (dextrose  in  urine}. — This  is  the  same  as 
Bottger's  reagent.  It  consists  of  a  solution  of 
2  parts  of  bismuth  subnitrate,  4  parts  of  potas- 
sium sodium  tartrate,  and  100  parts  of  8  per 
cent,  sodium  hydroxide.  Urine  containing  dex- 
trose becomes  black,  or  gives  a  black  precipitate 
with  this  reagent. 

O. 

OBERMAYER  (indican  in  urine). — The  urine  is 
treated  with  lead  acetate,  and  decanted,  and  then 
treated  with  strong  hydrochloric  acid  and  2  per 
cent,  ferric  chloride  solution.  In  the  presence 
of  indican,  a  blue  coloration  is  obtained,  and  the 
colour  can  be  extracted  with  chloroform. 

OBERMULLER  (cholesterol). — When  cholesterol  is 
just  melted  with  propionic  anhydride  it  gives,  on 
cooling,  a  violet  coloration,  which  changes  to 
blue,  then  to  green,  orange,  and  finally  red. 

OFFER  (uric  acid). — A  liquid  containing  uric  acid 
immediately  gives  a  brilliant  blue  precipitate 
when  treated  with  a  few  drops  of  phosphomo- 
lybdic  acid,  and  then  with  a  few  drops  of  potas- 
sium hydroxide. 

OGLIARO  (picrotoxine). — A  solution  of  picrotoxine 
in  strong  sulphuric  acid  gives  a  saffron-yellow 
coloration,  which  changes  to  green  on  the 
addition  of  potassium  bichromate. 

OGSTON  (chloral  hydrate). — A  solution  of  chloral 
hydrate  gives  a  brown  to  brownish-red  colora- 
tion, and  then  a  brown  precipitate,  when  heated 
with  ammonium  sulphide. 

ORLOW  (lecithin) . — An  alcoholic  solution  of  lecithin 
and  alloxan  becomes  first  pink  and  then  red,  and 
finally  gives  a  red  precipitate. 

ORLOW-HORST  (alkaloids  . — The  reagent  consists  of 
149 


REAGENTS  AND   REACTIONS. 

a  solution  of  ammonium  persulphate  in  sulphuric 
acid.  It  gives  distinctive  colorations  with 
various  alkaloids.  Thus,  it  gives  an  orange 
coloration  with  morphine ;  orange-red  with 
narcotine  ;  violet,  blood-red,  and  finally  yellow 
with  narceine  ;  and  green  and  then  blue  with 
apomorphine. 

OST  (dextrose). — The  reagent  consists  of  copper 
sulphate,  23-5  grms.  ;  sodium  carbonate,  250 
grms.  ;  and  potassium  carbonate,  100  grms.,  in  a 
litre  of  water  (see  SOLDAINI,  FEHLING). 

OSTERAG-ARNOLD  (fresh  and  boiled  milk). — The 
milk  is  treated  with  10  per  cent,  of  a  freshly- 
prepared  tincture  of  guaiacum.  Fresh  unboiled 
milk  gives  a  blue  coloration,  whilst  boiled  milk 
shows  a  yellow  tint. 

OTTO  (morphine}. — When  morphine  is  treated  with 
dilute  hydrochloric  acid,  and  then  with  ferric 
chloride  and  potassium  ferricyanide,  it  gives  a 
precipitate  of  Prussian  blue. 

OTTO  (picrotoxine). — When  picrotoxine  is  dissolved 
in  strong  sulphuric  acid  it  gives  a  yellow  solution, 
and,  on  heating,  is  carbonised. 

OTTO  (strychnine). — The  substance  is  mixed  with  a 
few  drops  of  a  dilute  solution  of  potassium 
bichromate,  and  a  glass  rod,  after  being  dipped 
into  the  liquid,  is  brought  into  contact  with 
strong  sulphuric  acid  in  a  porcelain  basin.  In 
the  presence  of  strychnine,  blue  streaks  are 
produced. 

OUDREJOVICH  (aceto-acetic  acid  in  urine}. — When 
5  c.c.  of  urine  are  acidified  with  5  drops  of  50  per 
cent,  aceto-acetic  acid,  and  a  sufficient  quantity 
of  a  0-2  per  cent,  solution  of  methylene-blue  to 
give  a  pronounced  blue  coloration  is  added,  and 
then  4  drops  of  tincture  of  iodine,  so  that  the 
liquid  becomes  red,  the  presence  of  aceto-acetic 
acid  is  indicated  by  the  liquid  becoming  blue 
again  after  a  minute,  and  then  green. 
150 


REAGENTS   AND   REACTIONS. 

OVERBECH  (wool  fibres). — On  impregnating  the 
fibres  with  a  10  per  cent,  aqueous  solution  of 
alloxan  and  treating  them,  after  draining  off 
the  excess  of  liquid,  with  gaseous  ammonia,  a 
carmine-red  coloration  is  obtained. 


P. 

PACINI  (solution  for  microscopy). — This  consists  of 
2  grms.  of  mercuric  chloride,  4  grms.  of  sodium 
chloride,  26  grms.  of  glycerin,  and  226  c.c.  of 
water.  For  use,  i  part  of  the  solution  is  diluted 
with  3  parts  of  water. 

PAGEL  (cobalt  salts). — This  is  Vogel's  reaction  (see 
VOGEL)  with  potassium  thiocyanate  and  ether. 

PAGENSTECKER  (copper  salts). — One  c.c.  of  cherry- 
laurel  water  and  10  drops  of  10  per  cent,  guaia- 
cum  tincture  are  mixed  in  a  porcelain  crucible, 
and  the  solution  to  be  tested  is  added.  In  the 
presence  of  copper  salts,  a  blue  coloration  is 
immediately  produced. 

PANUM  (albumin  in  urine). — The  urine  is  rendered 
strongly  acid  with  acetic  acid,  and  mixed  with 
an  equal  volume  of  a  saturated  solution  of  sodium 
chloride  and  sodium  sulphate.  In  the  presence  of 
albumin,  a  precipitate  is  obtained. 

PAPPENHEIM  (stain  for  microscopy). — Two  solutions 
are  prepared : — (i)  Liquid  phenol,  0-25  grm.  ; 
water,  100  c.c. ;  methyl  green,  i  grm.  (2)  Phenol, 
0-25  grm.  ;  pyronine,  i  grm.  ;  and  water,  100  c.c. 

PAUL  (biliary  pigments  in  urine). — Normal  urine, 
when  treated  with  methyl  violet,  does  not  affect 
the  colour  of  the  dyestuff,  whereas,  in  the 
presence  of  biliary  pigments,  the  violet  colora- 
tion changes  to  blood-red. 

PAVY  (dextrose  in  urine). — 120  c.c.  of  Fehling's 
solution  are  diluted  with  water  to  1,000  c.c.,  and 
300  c.c.  of  ammonia  solution  (sp.  gr.  0-88)  and 


REAGENTS  AND  REACTIONS. 

400  c.c.  of  sodium  hydroxide  solution  (sp.  gr. 
1-14)  are  added.  On  boiling  the  reagent  with  a 
solution  containing  dextrose,  it  is  decolorised. 

PAYEN  (mineral  acids  in  vinegar}. — 100  c.c.  of 
the  vinegar  are  boiled  for  thirty  minutes  with 
0-05  grm.  of  starch.  After  cooling,  the  liquid 
is  treated  with  a  potassium  iodide  solution  of 
iodine.  In  the  presence  of  mineral  acids,  no  blue 
coloration  appears. 

PELIGOT  (textile  fibres). — See  SCHWEITZER. 

PELLAGRI  (morphine). — On  evaporating  a  solution 
of  morphine  in  strong  hydrochloric  acid  with 
2  drops  of  sulphuric  acid,  a  purple-red  coloration 
is  produced. 

PELLAGRI  (codeine). — The  solution  of  the  substance 
in  0-5  c.c.  of  strong  hydrochloric  acid  is  heated 
on  the  water-bath  with  3  drops  of  sulphuric 
acid,  until  the  hydrochloric  acid  has  been 
expelled.  After  being  heated  for  fifteen  minutes, 
the  residue,  which  is  of  a  violet  colour,  is 
dissolved  in  2  c.c.  of  water,  and  the  solution 
treated  with  a  few  drops  of  hydrochloric  acid, 
then  neutralised  with  sodium  bicarbonate,  and 
treated  with  3  drops  of  tincture  of  iodine.  An 
emerald-green  coloration  is  obtained,  and,  on 
shaking  the  liquid  with  ether,  the  ethereal  layer 
becomes  red,  whilst  the  aqueous  layer  remains 
green. 

PELOUZE  (dextrose). — See  MOORE. 

PENOT  (oils). — The  reaction  consists  in  treating 
10  c.c.  of  the  oil  with  i  grm.  of  a  mixture  of 
potassium  bichromate  and  sulphuric  acid. 
Various  colorations  are  produced. 

PENTZOLD  (acetone  in  urine). — The  urine  is  acidified 
and  distilled,  and  the  distillate  is  added  to  an 
aqueous  solution  of  ortho-nitrobenzaldehyde, 
which  is  then  made  alkaline  with  sodium 
hydroxide.  In  the  presence  of  acetone,  a  yellow 
coloration,  changing  to  green,  is  obtained,  whilst 
152 


REAGENTS  AND   REACTIONS. 

indigo  is  deposited,  and  may  be  extracted  with 
chloroform. 

PENTZOLD  (dextrose). — One  part  of  diazo-benzene- 
sulphonic  acid  is  dissolved  in  60  parts  of  water, 
and  the  solution  is  rendered  alkaline  with 
2  drops  of  potassium  hydroxide  solution.  This 
reagent  is  added  to  an  equal  volume  of  the 
liquid  under  examination,  which  has  been  made 
strongly  alkaline,  and  the  mixture  is  allowed  to 
stand.  In  the  presence  of  dextrose,  it  becomes 
yellowish-red  or  bright  red,  and  the  colour  then 
changes  to  dark  red.  The  red  colours  show 
bluish  reflections. 

PENTZOLD  (naphthalene  in  urine). — One  c.c.  of 
strong  sulphuric  acid  is  dropped  on  to  the  urine. 
If  naphthalene  is  present,  the  urine  above  the 
acid  layer  becomes  green,  whilst,  subsequently, 
the  acid  also  assumes  the  same  colour. 

PENTZOLD-FISCHER  (phenol).  --On  treating  a 
strongly-alkaline  solution  of  phenol  with  diazo- 
benzenesulphonic  acid,  a  red  coloration  is  ob- 
tained. 

PERTUSI-GASTALDI  (hydrocyanic  acid). — The  re- 
agent consists  of  i  drop  of  copper  acetate 
solution,  5  drops  of  a  saturated  solution  of 
benzidine  acetate,  and  0-5  c.c.  of  water.  When 
hydrocyanic  acid  is  passed  through  this  liquid, 
a  bright  blue  coloration  is  produced.  The 
reaction  is  capable  of  detecting  0-000007  gim. 
of  hydrocyanic  acid  in  the  form  of  an  alkali 
cyanide  in  10  c.c.  of  water. 

PESCI  (alkaloids). — The  solution  to  be  tested  for 
alkaloids  is  treated  with  a  reagent  consisting 
of  a  mixture  of  solutions  of  copper  sulphate  and 
sodium  thiosulphate,  and  is  then  acidified  with 
dilute  sulphuric  acid. 

PETRI    (proteins). — On   treating   a   solution   of   a 
protein  with  a  solution  of  diazo-benzenesulphonic 
acid,    a    faint   yellow    coloration    is    produced. 
153 


REAGENTS   AND   REACTIONS. 

When  the  liquid  is  then  made  alkaline,  it  becomes 
orange-yellow  to  brown,  and,  on  shaking,  gives  a 
red  froth. 

PETTENKOFER  (biliary  acids  in  urine). — A  small 
quantity  of  the  bile  substance  is  dissolved  in  hot 
strong  sulphuric  acid,  or  the  liquid  containing  the 
biliary  acids  (e.g.,  urine)  is  mixed  with  strong 
sulphuric  acid,  the  temperature  not  being  allowed 
to  exceed  60°  to  70°  C.  in  either  case.  A  10  per 
cent,  solution  of  cane  sugar  is  then  added,  drop 
by  drop,  with  constant  stirring.  In  the  presence 
of  biliary  acids,  a  bright  red  coloration  is  pro- 
duced, which  persists  for  a  considerable  time, 
and  becomes  violet  after  twenty-four  hours.  The 
red  liquid  shows  a  spectrum  with  two  charac- 
teristic absorption  bands. 

PICK  (stain  for  bacteriology). — This  consists  of 
8  drops  of  Ziehl's  carbolic  magenta,  8  drops  of  a 
concentrated  alcoholic  solution  of  methylene- 
blue,  and  20  c.c.  of  water. 

PILHASTRY  (formaldehyde). — On  mixing  i  c.c.  of  a 
solution  of  formaldehyde  with  2  drops  of  a 
reagent  consisting  of  a  solution  of  i  grm.  of 
phenylhydrazine  hydrochloride  and  1-5  c.c.  of 
sodium  acetate  solution  in  100  c.c.  of  water,  and 
adding  2  drops  of  sulphuric  acid,  a  green  colora- 
tion is  obtained. 

PiNETTE-ScHMiDT  (saccharin). — The  residue  ob- 
tained by  evaporating  an  ethereal  extract  of 
saccharin  from  the  substance,  is  mixed  with 
sodium  hydroxide,  and  heated  for  thirty  minutes 
at  250°  C.  The  product  is  dissolved  in  water, 
acidified  with  sulphuric  acid,  and  shaken  with 
chloroform,  or  with  ether.  The  extract  is  sepa- 
rated, the  solvent  evaporated,  and  the  residue 
taken  up  with  a  little  water,  and  treated  with  a 
dilute  solution  of  ferric  chloride.  In  the  presence 
of  saccharin,  a  violet  coloration  (formation  of 
salicylic  acid)  will  be  produced. 
154 


REAGENTS  AND  REACTIONS. 

PIOTROWSKI  (proteins). — On  heating  the  solution 
with  an  excess  of  sodium  hydroxide  solution  and 
i  to  2  drops  of  a  dilute  solution  of  copper  sul- 
phate, a  violet  coloration  will  be  produced  (biuret 
reaction) . 

PIRIA-STAEDELER  (tyrosin). — The  tyrosin  is  dis- 
solved in  cold  strong  sulphuric  acid,  and  the 
solution  diluted  with  water,  neutralised  with 
calcium  carbonate,  and  filtered.  On  adding  a 
neutral  solution  of  ferric  chloride  to  the  nitrate, 
a  violet  coloration  will  be  obtained. 

PIUTTI  (lignin). — Lignin  gives  a  yellow  coloration 
when  treated  with  o-bromophenetidine. 

PLANTA  (alkaloids). — The  reagent  is  practically  the 
same  as  that  of  Mayer. 

PLUCxGE  (phenols). — This  is  identical  with  Millon's 
reagent. 

PLUGGE  (gum  ammoniacum) . — On  adding  a  drop  of 
a  solution  of  sodium  hypochlorite  to  a  solution 
containing  gum  ammoniacum,  in  the  presence 
of  soda  lye,  a  violet  coloration  is  immediately 
produced. 

PLUGGE  (cerium  oxide). — When  an  alkaline  solution 
of  a  cerium  salt  is  evaporated,  and  the  residue 
treated  with  a  few  drops  of  a  i  per  cent,  solution 
of  strychnine  in  dilute  sulphuric  acid,  there  is 
produced  a  bright  blue  coloration,  which  dis- 
appears, and  leaves  a  permanent  cherry-red 
coloration. 

PODW  YSSOTZKI  (emetine) . — A  recently-prepared 
solution  of  ammonium  phosphomolybdate  in 
strong  sulphuric  acid  turns  brown  on  contact 
with  emetine.  On  adding  strong  hydrochloric 
acid,  a  blue  coloration  is  produced. 

POLLACCI  (albumin  in  urine). — One  grm.  of  tartaric 
acid  and  5  grms.  of  mercuric  chloride  are  dis- 
solved in  100  c.c.  of  water,  and  100  c.c.  of  40 
per  cent,  formalin  are  added  to  the  solution. 
Two  c.c.  of  this  reagent  are  added  to  4  c.c.  of  the 
155 


REAGENTS  AND   REACTIONS. 

urine,  so  as  to  form  two  separate  layers,  and,  in 
the  presence  of  albumin,  a  white  ring  is  formed, 
and  diffuses  into  the  liquid. 

POLLACCI  (quinine). — A  mixture  of  o-oi  grm.  of  the 
substance,  i  c.c.  of  water,  2  drops  of  sulphuric 
acid,  and  a  trace  of  lead  dioxide  is  heated  to 
boiling,  and  then  diluted  with  3  to  4  c.c.  of  water. 
On  adding  ammonia  to  the  clear  liquid,  the  forma- 
tion of  a  green  ring  indicates  the  presence  of 
quinine. 

POLLACCI  (phenol). — One  drop  of  aniline  is  mixed 
with  30  c.c.  of  water,  10  drops  of  this  liquid 
are  diluted  with  10  c.c.  of  water,  and  sodium 
hypochlorite  is  added,  until  a  blue  coloration  is 
produced.  As  soon  as  this  coloration  has 
disappeared,  ammonia  is  added,  and  then  the 
solution  to  be  tested.  In  the  presence  of  phenol, 
the  blue  coloration  returns,  and  is  changed  to  red 
on  the  addition  of  an  acid. 

POLLACCI  (formaldehyde] . — A  solution  of  codeine  in 
sulphuric  acid  gives  a  violet  coloration  with 
aqueous  solutions  of  formaldehyde. 

POLLACK  (nitric  acid). — The  reagent  is  prepared  by 
dissolving  o-oi  grm.  of  diphenylamine  in  a 
mixture  of  20  grms.  of  sulphuric  acid  (66°  Be.) 
and  60  c.c.  of  water,  and  making  the  solution  up 
to  100  c.c.  with  sulphuric  acid.  This  reagent 
gives  the  well-known  blue  coloration  on  contact 
with  nitric  acid. 

POLLITI  (dextrose).  --  The  reagent  consists  of 
24-95  grms.  of  copper  sulphate,  140  grms.  of 
potassium  sodium  tartrate,  and  25  grms.  of 
sodium  hydroxide  in  a  litre  of  water.  The 
solution  under  examination  is  boiled  with  an 
excess  of  the  reagent,  and  the  excess  of  copper 
sulphate  is  titrated  with  N-sodium  thiosulphate 
solution. 

POSSETTO-ISSOGLIO  (saccharin). — On  melting  a 
little  saccharin  with  a  fragment  of  sodium, 
156 


REAGENTS   AND   REACTIONS. 

dissolving  the  mass  in  water,  adding  hydro- 
chloric acid,  and  treating  the  solution  with 
^-amino-dimethylaniline,  and  then  with  ferric 
chloride,  a  blue  coloration  (formation  of  methy- 
lene-blue)  is  obtained. 

POSSNER  (peptone  in  urine}. — The  urine  is  made 
alkaline,  and  treated  with  a  dilute  solution  of 
copper  sulphate  so  as  to  form  two  layers.  In  the 
presence  of  peptones,  a  violet  ring  is  produced  at 
the  zone  of  contact  (see  PIOTROWSKI  ;  ROSE). 

POUTET  (vegetable  oils). — Ten  grms.  of  the  oil  are 
treated  in  a  test-tube  with  5  grms.  of  nitric  acid 
(sp.  gr.  40°  to  42°  Be.)  and  i  grm.  of  mercury. 
After  being  shaken  for  three  minutes,  the  tube  is 
put  aside  for  twenty  minutes,  and  is  then  shaken 
again  for  one  minute.  The  mass  solidifies  more 
or  less  rapidly  and  completely,  according  to  the 
constitution  of  the  oil  and  the  temperature. 
Thus,  olive  oil  hardens  within  fifteen  minutes  at 
14°  C.,  and  after  sixty-seven  minutes  at  18°  to 
19°  C.  ;  whilst  arachis  oil  hardens  in  fifteen 
minuter  at  14°  C.,  and  in  152  minutes  at  18°  to 
19°  C.  (Elaidin  reaction). 

PREYER  (hydrocyanic  acid}. — A  very  dilute  alco- 
holic solution  of  guaiacum  resin  is  treated  with  a 
very  small  amount  of  copper  sulphate  solution. 
On  applying  a  glass  rod,  which  has  been  moistened 
with  hydrocyanic  acid,  to  a  little  of  this  reagent 
in  a  porcelain  dish,  blue  streaks  are  produced, 
and,  on  shaking  the  dish,  the  whole  liquid 
becomes  blue. 

PROSCH  (rhubarb  in  urine}. — The  urine  is  treated 
with  hydrochloric  acid,  and  shaken  with  xylene, 
and  the  xylene  extract  is  separated,  and  treated 
with  a  solution  of  potassium  hydroxide.  If  the 
urine  contained  rhubarb,  a  rose-coloured  ring 
will  be  formed  at  the  zone  of  contact  of  the 
liquids.  By  using  chloroform  instead  of  xylene 
for  the  extraction  a  violet  ring  will  be  obtained. 
157 


REAGENTS   AND   REACTIONS. 

PUSCH  (tartaric  acid  in  citric  acid}. — One  grm.  of 
the  citric  acid  is  treated  for  an  hour  on  the  water- 
bath  with  10  grms.  of  strong  sulphuric  acid.  Pure 
citric  acid  gives  a  yellow  coloration,  but  in  the 
presence  of  tartaric  acid  a  brown  or  brownish- 
red  coloration  will  be  produced. 


R. 

RAABE  (albumin  in  urine). — The  filtered  urine  is 
treated  with  crystallised  trichloracetic  acid. 
In  the  presence  of  albumin  a  turbidity  is 
produced. 

RABL  (stain  for  microscopy}. — This  consists  of  8  c.c. 
of  a  10  per  cent,  solution  of  chromic  acid,  200  c.c. 
of  water,  and  5  drops  of  formic  acid  (sp.  gr.  1-2). 

RABY  (codeine). — On  treating  codeine  with  sodium 
hypochlorite  and  with  a  few  drops  of  sulphuric 
acid  it  gives  a  blue  coloration. 

RABUTEAU  (hydrochloric  acid  in  gastric  juice}. — 
A  solution  of  50  c.c.  of  starch  paste,  i  grm.  of 
potassium  iodate,  and  0-5  grm.  of  potassium 
iodide  is  coloured  blue  by  free  hydrochloric  acid 
in  the  filtrate  from  gastric  juice. 

RAFFAELE  (proteins}. — This  is  a  modification  of 
Spiegler's  reagent,  in  which  the  acetic  acid  is 
replaced  by  hydrochloric  acid. 

RASMUSSEN  (hexoses}. — One  c.c.  of  the  sugar 
solution  is  treated  with  16  to  20  drops  of  a  10 
per  cent,  alcoholic  solution  of  diphenylamine, 
and  then  with  i  c.c.  of  strong  hydrochloric  acid, 
and  heated  until  the  colour  disappears.  The 
liquid  is  then  cooled  and  extracted  with  ether, 
which  in  the  presence  of  hexoses  is  coloured  blue. 

RASPAIL  (proteins}. — Proteins  are  coloured  red 
when  treated  with  sugar  and  sulphuric  acid 
(see  SCHULTZE). 

REICH  (cane  sugar} . — A  solution  of  cane  sugar  gives 

158 


REAGENTS   AND   REACTIONS. 

a  violet  coloration  when  treated  with  a  solution 
of  cobalt  nitrate,  followed  by  sodium  hydroxide. 

REICH  (glycerin). — When  a  mixture  in  equal  parts 
of  glycerin,  phenol,  and  sulphuric  acid  is  heated 
to  120°  C.,  the  residue  cooled,  taken  up  with 
water,  and  the  solution  treated  with  ammonia, 
the  brown  liquid  changes  to  carmine- red. 

REICHARD  (santonine}.- — When  santonine  is  heated 
with  an  alcoholic  solution  of  potassium  hydroxide, 
a  carmine-red  coloration  is  produced  ;  but  on 
heating  santonine  with  strong  sulphuric  acid,  a 
blue  coloration  is  obtained. 

REICHARDT  (nitric  acid}. — A  solution  of  brucine 
in  strong  sulphuric  acid  gives  an  intense  red 
coloration  with  nitric  acid.  Sensitiveness  = 

1  :  256,000. 

REICHL  (proteins). — The  solution  is  treated  with 

2  to  3  drops  of  an  alcoholic  solution  of  benzal- 
dehyde,   a  certain   quantity  of  sulphuric   acid 
(i  :  i),  and  a  few  drops  of  ferric  chloride  solution. 
After  some  time  in  the  cold,  and  immediately 
on  heating,  an  intense  blue  coloration  is  pro- 
duced. 

REINSCH  (arsenic). — A  piece  of  copper  foil  is 
immersed  in  the  solution  previously  acidified 
with  hydrochloric  acid.  In  the  presence  of 
arsenic,  a  grey  deposit  of  copper  arsenide  is 
formed  upon  the  copper. 

RENARD  (arachis  oil). — The  test  is  based  upon  the 
separation  of  arachidic  and  lignoceric  acids  from 
the  fatty  acids  of  the  oil.  These  acids  form 
characteristic  crystals  with  definite  melting 
points. 

REUTER  (chloral). — On  heating  chloral  with  phena- 
cetin,  a  bright  violet  coloration  is  obtained. 

REYNOLD  (acetone  in  urine}. — The  urine  is  treated 

with  mercuric  chloride  and  an  excess  of  alcoholic 

potassium  hydroxide  solution,  and  filtered.     In 

the  presence  of  acetone,  the  filtrate  gives  a  black 

159 


REAGENTS   AND   REACTIONS. 

precipitate  of  mercuric  sulphide,  when  treated 
with  hydrogen  sulphide. 

RICHARDSON  (a-  and  p-naphthol). — The  solution  of 
the  naphthol  in  sodium  hydroxide  solution  is 
treated  with  a  small  quantity  of  a  reagent 
consisting  of  a  mixture  of  0-05  grm.  of  sul- 
phanilic  acid  in  5  c.c.  of  N-sodium  hydroxide 
solution,  and  0-02  grm.  of  sodium  nitrite  in 
5  c.c.  of  N-sulphuric  acid.  Under  such  condi- 
tions, a-naphthol  gives  a  deep  blood-red  colora- 
tion, whilst  /3-naphthol  gives  a  reddish-yellow 
coloration. 

RIEGLER  (aceto-acetic  acid  in  urine). — The  reagent 
consists  of  a  solution  of  iodic  acid.  This  is  added 
to  the  urine,  previously  acidified  with  sulphuric 
acid,  and,  in  the  presence  of  aceto-acetic  acid, 
produces  a  red  coloration. 

RIEGLER  (nitrous  acid). — The  reagent  consists  of 
an  aqueous  solution  of  sodium  naphthionate  and 
/2-naphthol.  On  adding  a  few  drops  thereof  to 
the  liquid  to  be  tested,  then  hydrochloric  acid, 
and  finally  ammonia,  a  red  ring  is  produced  when 
nitrous  acid  is  present. 

RIEGLER  (uric  acid). — The  reagent  is  prepared  by 
heating  0-2  grm.  of  nitro-aniline  with  10  c.c. 
'  of  water  and  15  drops  of  strong  sulphuric  acid, 
shaking  the  solution  with  20  c.c.  of  water,  and, 
when  cold,  adding  10  c.c.  0f  a  2-5  per  cent, 
solution  of  sodium  nitrite  and  60  c.c.  of  water, 
and  filtering  the  liquid.  The  addition  of  10  per 
cent,  sodium  hydroxide  solution  and  a  few  drops 
of  this  reagent  to  uric  acid,  whether  in  the  solid 
form  or  in  solution,  causes  a  blue  or  green  colora- 
tion to  appear. 

RIEGLER  (albumin  in  urine). — Ten  c.c.  of  the  urine 
are  treated  with  20  drops  of  a  reagent  consisting 
of  8  grms.  of  asaprol  and  8  grms.  of  citric  acid  in 
200  c.c.  of  water.  In  the  presence  of  albumin,  a 
turbidity  or  precipitate  is  obtained. 
160 


REAGENTS   AND   REACTIONS. 

RIEGLER  (formaldehyde  in  milk). — The  milk  is 
diluted,  and  shaken  with  phenylhydrazine  hydro- 
chloride  and  sodium  hydroxide  solution.  In  the 
presence  of  formaldehyde  a  pink  coloration  is 
produced. 

RIEGLER  (sugar). — A  mixture  of  o-io  grm.  of 
phenylhydrazine  hydrochloride  and  0-5  grm.  of 
crystalline  sodium  acetate  is  heated  with  i  c.c. 
of  the  solution  under  examination  until  the 
liquid  begins  to  boil,  after  which  the  heating  is 
stopped,  and  30  drops  of  a  30  per  cent,  solution 
of  sodium  hydroxide  are  added.  In  the  presence 
of  sugar,  the  liquid  becomes  violet-red. 
RIMINI  (formaldehyde). — On  adding  to  a  solution 
containing  even  a  minute  quantity  of  formalde- 
hyde a  small  amount  of  phenylhydrazine  solu- 
tion, then  sodium  nitroprusside,  and  finally 
potassium  hydroxide,  a  bright  blue  coloration  is 
produced. 

RIMINI  (acetone). — Acetone  gives  a  violet-red 
coloration  when  treated  with  sodium  nitro- 
prusside and  an  aliphatic  primary  amine. 
RINNMANN  (zinc  salts). — On  heating  zinc  salts 
on  charcoal  with  a  solution  of  cobalt  nitrate,  an 
infusible  green  mass  is  left. 

RITSERT  (acetanilide,  phenacetin). — The  substance 
is  boiled  with  hydrochloric  acid,  and,  after 
cooling,  is  treated  with  chlorine  water.  In  the 
presence  of  acetanilide,  a  blue  coloration  is  pro- 
duced, whilst  phenacetin  under  the  same  condi- 
tions gives  a  ruby-red  coloration. 
RITSERT  (sulphonal). — When  heated  with  pyro- 
gallol,  sulphonal  emits  the  unpleasant  odour  of 
mercaptan. 

ROBINET  (morphine). — When  a  neutral  solution  of 
a  morphine  salt  is  treated  with  a  neutral  dilute 
solution  of  ferric  chloride,  it  gives  a  fugitive  blue 
coloration. 

ROCHLEDER  (caffeine). — This  is  the  well-known 
R.R.  161  ii 


REAGENTS   AND   REACTIONS. 

murexide  test.  The  substance  is  gently  heated 
with  2  to  3  drops  of  nitric  acid  on  the  water-bath, 
and  the  residue  is  treated  with  ammonia  solution. 
In  the  presence  of  caffeine,  there  is  produced  a 
purple-red  coloration,  which,  on  the  addition  of 
an  alkali,  becomes  blue  or  violet-blue. 

ROGERS  (tin  salts). — Salts  of  tin  give  a  blue 
coloration  with  ammonium  molybdate  solution. 
Sensitiveness  =  i  :  250,000. 

ROMAN-DELLUC  (urobilin  in  urine). — One  hundred 
c.c.  of  the  urine  are  shaken  in  a  separating  funnel 
with  10  drops  of  hydrochloric  acid,  and,  subse- 
quently, with  20  c.c.  of  chloroform,  and  allowed 
to  stand.  The  chloroform  layer  is  separated,  and 
an  alcoholic  o-i  per  cent,  solution  of  zinc  acetate 
is  added,  without  mixing  the  liquids.  At  the  zone 
of  contact  of  the  two  layers  a  green  ring,  charac- 
teristic of  urobilin,  when  present,  will  be  pro- 
duced, and,  on  shaking  the  mixture,  the  green 
colour  will  be  diffused. 

ROSE  (albumin  in  urine). — The  urine  is  treated 
with  sodium  hydroxide  solution,  and  a  2  per 
cent,  solution  of  copper  sulphate  is  added,  drop 
by  drop,  with  constant  agitation.  In  the 
presence  of  albumin,  the  liquid  becomes  red, 
then  violet,  and  finally  deep  blue  (biuret 
reaction). 

ROSENBACH  (biliary  pigments  in  urine). — The 
addition  of  a  few  drops  of  a  5  per  cent,  solution 
of  chromic  acid  produces  a  green  coloration  when 
biliary  pigments  are  present. 

ROSENBACH  (albumin  in  urine). — A  few  drops  of 
50  per  cent,  chromic  acid  are  added  to  the  urine 
without  mixing  the  liquids.  In  the  presence  of 
albumin,  an  opaque  ring  is  formed  at  the  zone  of 
contact. 

ROSIN  (biliary  pigments  in  urine). — When  icteric 
urine  is  treated  with  tincture  of  iodine,  diluted 
with  alcohol,  until  a  madder  coloration  is  ob- 
162 


REAGENTS  AND   REACTIONS. 

tained,  and  in  such  a  way  that  the  liquids  do 
not  mix,  a  grass-green  ring  is  produced. 

ROUSSIN  (nicotine}. — On  mixing  an  ethereal  solu- 
tion of  nicotine  (i  :  500)  with  an  ethereal  solution 
of  iodine  (i  :  75),  fine  crystals  of  iodonicotine  are 
obtained. 

Roux  (stain  for  bacteriology). — Two  solutions  are 
prepared  : — (A)  Dahlia-violet,  i  grm.  ;  90  per 
cent,  alcohol,  10  c.c.  ;  and  water,  10  c.c. 
(B)  Methyl  green,  i  grm.  ;  90  per  cent,  alcohol, 
10  c.c.  ;  and  water,  90  c.c.  One  third  of  solution 
A  is  mixed  with  two-thirds  of  solution  B,  both 
solutions  having  been  allowed  to  stand  for 
twenty-five  hours,  and  separately  filtered. 

RUBNER  (dextrose  and  lactose}. — Dilute  basic  lead 
acetate  solution  and  ammonia  are  added  drop 
by  drop  to  the  liquid  under  examination,  until 
a  permanent  precipitate  is  obtained.  In  the 
presence  of  dextrose  or  lactose,  this  becomes 
yellow,  and  then  flesh-coloured,  the  changes 
being  more  rapid  on  applying  heat. 

RUBNER  (carbon  monoxide  in  blood}. — One  part 
of  the  blood  is  shaken  for  one  minute  with  4  to 
5  parts  (by  volume)  of  lead  acetate  solution. 
Normal  blood  becomes  blackish-brown,  whilst 
blood  containing  carbon  monoxide  retains  its 
bright  red  colour. 

RUGGERI  (dulcine). — When  a  small  quantity  of 
dulcine  is  treated  with  a  few  c.c.  of  a  6  per  cent, 
solution  of  silver  nitrate,  or  a  5  per  cent,  solution 
of  mercuric  chloride,  and  evaporated  to  dryness 
on  the  water-bath,  the  residue,  after  being  heated 
for  some  time,  assumes  a  fine  violet  colour, 
which  becomes  more  pronounced  if  the  heating 
is  continued  on  a  sand-bath  at  160°  C.  On 
treating  the  residue,  while  still  hot,  with  alcohol, 
a  wine-red  solution  is  obtained. 

RUNGE  (aniline). — Aniline  treated  with  calcium 
hypochlorite  solution  gives  a  purple-violet 


REAGENTS  AND   REACTIONS. 

coloration,  which  changes  to  pink  on  the  addition 
of  acids. 
RUSTING  (salts  of  cobalts). — See  VOGEL. 


S. 

SABANIN-LASKOWSKY  (citric  acid). — When  citric 
acid  (o-oi  grm.)  is  heated  with  six  times  its 
weight  of  ammonia  solution  in  a  sealed  tube  for 
some  hours  at  118°  to  120°  C.,  and  is  then 
transferred  to  a  porcelain  basin,  it  should,  after 
some  hours,  become  blue  and  then  green 
(differentiation  from  oxalic,  malic,  and  tartaric 
acids) . 

SADLUND  (iodine  in  urine). — Five  c.c.  of  the  urine 
are  treated  with  i  c.c.  of  dilute  sulphuric  acid, 
and  2  to  3  drops  of  sodium  nitrite  solution 
(0-2  in  100).  On  then  shaking  the  urine  with 
carbon  bisulphide,  iodine,  if  present,  is  extracted, 
giving  the  usual  violet  solution. 

SAHLI  (reagent  for  microscopy). — This  consists  of 
a  solution  of  0-75  grm.  of  methylene-blue  and 
0-8  grm.  of  borax  in  80  c.c.  of  water. 

SAILLET  (urobilinogen  in  urine) . — This  reaction  will 
detect  urobilinogen  in  the  presence  of  urobilin. 
One  hundred  c.c.  of  the  urine,  which  has  been 
recently  emitted  and  kept  in  the  dark,  are 
acidified  with  10  drops  of  acetic  acid,  and  shaken 
with  an  equal  volume  of  ethyl  acetate.  The 
extract  is  shaken  with  a  small  quantity  of  water, 
which  extracts  the  urobilin,  forming  a  brown 
solution,  whilst  the  urobilinogen  remains  in  the 
ethylacetate,  and,  on  exposure  to  the  light, 
changes  into  urobilin. 

SALKOWSKI  (cholesterol). — On  shaking  a  solution  of 

a  few  centigrms.   of  cholesterol  in  chloroform 

with  an  equal  volume  of  strong  sulphuric  acid, 

the  chloroform  becomes  blood-red,  whilst  the 

164 


• 


•  urmjM     UULLtGE 

91  PHARMACY     " 

REAGENTS  AND   REACTIONS. 

acid  shows  a  green  fluorescence.  When  a  little 
of  the  chloroform  solution  is  treated  with  water, 
it  gives  a  blue  coloration,  which  changes  to  green, 
and  finally  to  yellow. 

SALKOWSKI  (phenol). — When  a  solution  of  phenol 
is  treated  with  about  a  fourth  of  its  volume  of 
ammonia  solution,  and  then  with  a  few  drops  of 
calcium  hypochlorite  solution,  and  the  mixture 
slightly  heated,  a  blue  coloration  is  obtained. 

SALKOWSKI  (indol). — On  adding  to  a  solution  of 
indol  a  little  nitric  acid,  and  then,  drop  by  drop, 
a  2  per  cent,  solution  of  potassium  nitrite,  a  red 
coloration,  and  subsequently  a  red  precipitate  is 
obtained. 

SALKOWSKI  (carbon  monoxide  in  blood). — (i)  The 
blood  is  diluted  with  twenty  times  its  volume  of 
water,  and  a  small  quantity  of  the  liquid  is  treated 
with  an  equal  volume  of  sodium  hydroxide 
solution  (sp.  gr.  1-38).  Blood  containing  carbon 
monoxide  first  becomes  turbid  and  then  turns 
bright  red,  whilst  flocculent  particles  of  the  same 
colour  separate  and  float  upon  the  surface  of  the 
liquid.  Normal  blood,  under  the  same  conditions, 
becomes  dirty  brown  in  colour. 

(2)  A  mixture  of  0-9  c.c.  of  the  blood,  50  c.c. 
of  water,  a;nd  25  c.c.  of  an  aqueous  solution  of 
hydrogen  sulphide  becomes  dirty  green  within  a 
few  minutes  if  carbon  monoxide  is  not  present. 
Blood  containing  the  gas  does  not  alter  in  colour 
on  the  addition  of  hydrogen  sulphide. 

SALKOWSKI  (pentosans  in  urine). — (i)  The  urine 
under  examination  is  mixed  with  an  equal 
volume  of  strong  hydrochloric  acid,  and  heated 
with  a  small  quantity  of  orcinol.  In  the  presence 
of  pentosans,  the  mixture  assumes  a  fugitive  red 
or  violet  colour,  and  then  becomes  green.  Amyl 
alcohol  extracts  from  this  liquid  a  substance 
which  is  first  red  and  then  green. 

(2)  Phloroglucinol  is   dissolved  in   6   c.c.    of 
165 


REAGENTS  AND   REACTIONS. 

strong  hydrochloric  acid,  leaving  a  slight  excess 
undissolved.  The  solution  is  divided  into  two 
parts,  and  to  one  of  these  is  added  0-5  c.c.  of  the 
urine  under  examination,  whilst  the  other 
receives  an  equal  quantity  of  normal  urine. 
Both  test-tubes  are  immersed  in  boiling  water, 
and  examined  after  a  short  time.  In  the  case  of 
urine  containing  pentosans,  a  red  zone  will  be 
formed,  and  the  colour  well  diffused  into  the  rest 
of  the  liquid,  whilst  normal  urine  will  show  no 
alteration  in  colour. 

SALKOWSKI  (peptones  in  urine}. — Fifty  c.c.  of  the 
urine  are  acidified  with  50  c.c.  of  hydrochloric 
acid,  and  heated  with  phosphotungstic  acid.  The 
liquid  is  filtered,  and  the  precipitate  is  dissolved 
in  8  c.c.  of  water  mixed  with  0*5  c.c.  of  sodium 
hydroxide  solution  (sp.  gr.  1-16).  The  bright 
blue  liquid  thus  obtained  becomes  turbid  on 
heating,  and  changes  its  colour  to  yellow.  It  is 
cooled,  and  treated,  drop  by  drop,  with  a  dilute 
solution  of  copper  sulphate.  In  the  presence  of 
peptone,  the  liquid  turns  red. 

SANGLE-FERRIERE  (abrastol  in  wine). — 200  c.c.  of 
the  wine  are  acidified  with  8  c.c.  of  hydrochloric 
acid,  and  boiled  for  an  hour  beneath  a  reflux 
condenser.  The  liquid  is  then  cooled,  and 
extracted  with  petroleum  spirit,  and  the  extract 
is  allowed  to  evaporate  spontaneously.  The 
residue  is  taken  up  with  10  c.c.  of  chloroform, 
and  the  solution  is  treated  with  a  fragment  of 
potassium  hydroxide  and  a  few  drops  of  alcohol, 
and  boiled  for  two  minutes.  In  the  presence  of 
abrastol,  a  deep  blue  coloration  is  produced,  which 
rapidly  changes  to  green,  and  then  to  yellow. 

SANNA-PINTUS  (abrastol  in  wine). — Ten  c.c.  of  the 
wine  are  decolorised,  in  the  cold,  with  2  grms.  of 
animal  charcoal,  and  the  decolorised  liquid  is 
treated  with  an  equal  volume  of  a  solution  of 
mercuric  nitrate  containing  nitric  acid  (100  grms. 
166 


REAGENTS  AND   REACTIONS. 

of  mercury  dissolved  in  97  c.c.  of  nitric  acid  of 
42°  Be.  and  diluted  with  35  c.c.  of  water).  A 
yellow  coloration,  appearing  golden  by  reflected 
light,  indicates  the  presence  of  abrastol. 

SCHAER  (morphine). — A  neutral  solution  of  mor- 
phine gives  a  blue  coloration,  when  treated  with  a 
very  dilute  solution  of  ferric  chloride. 

SCHAER  (blood}. — A  75  per  cent,  solution  of  chloral 
hydrate  containing  the  blood  is  mixed  with  a 
dilute  solution  of  aloine  and  chloral  hydrate,  and 
hydrogen  peroxide  is  added  to  the  mixture.  A 
violet-red  zone,  which  is  formed  after  a  short 
time,  indicates  the  presence  of  blood. 

SCHAFFER  (cocaine). — When  0-02  grm.  of  cocaine 
hydrochloride  is  dissolved  in  i  c.c.  of  sulphuric 
acid  and  a  drop  of  water,  a  colourless  solution  is 
obtained  ;  but,  on  adding  a  drop  of  potassium 
bichromate  solution,  a  precipitate,  which  rapidly 
disappears,  is  formed,  whilst  the  reddish-yellow 
colour  of  the  solution  changes  to  green,  on 
heating. 

SCHAFFER  (unboiled  and  boiled  milk). — Ten  c.c.  of 
the  milk  are  shaken  with  I  drop  of  0-2  per  cent. 
hydrogen  peroxide  solution,  and  2  drops  of  a 
2  per  cent,  solution  of  />-phenylenediamine. 
Unboiled  milk  gives  a  blue  coloration. 

SCHAFFER  (nitrites  in  urine). — Four  c.c.  of  the 
urine  are  decolorised  with  animal  charcoal,  and 
treated  with  4  c.c.  of  10  per  cent,  acetic  acid  and 
with  3  drops,  at  most,  of  5  per  cent,  potassium 
ferrocyanide  solution.  In  the  presence  of  nitrites, 
an  intense  yellow  coloration  is  produced.  Sensi- 
tiveness =  0-000045  grm.  of  N2O3  in  100  c.c. 

SCHARGE  (cocaine] . — See  SCHAFFER. 

SCHEIBLER  (alkaloids). — The  reagent  consists  of 
phosphotungstic  acid.  Ordinary  sodium  tung- 
state  is  dissolved  in  boiling  water  containing 
about  half  its  weight  of  phosphoric  acid 
(sp.  gr.  1*13).  On  evaporating  the  liquid, 
167 


REAGENTS  AND   REACTIONS. 

crystals  of  phosphotungstic  acid  are  left,  and  a 
10  per  cent,  solution  of  these  constitutes  the 
reagent.  It  gives  white  precipitates  with  solu- 
tion of  alkaloids.  It  also  precipitates  albumoses 
and  peptones. 

SCHERER  (phosphorus).  —  The  substance  under 
examination  (e.g.,  contents  of  the  stomach), 
which  ought  to  have  an  acid  reaction,  is  placed 
in  a  stoppered  flask,  and  within  the  neck  of  the 
flask  are  suspended  two  strips  of  filter-paper,  one 
impregnated  with  silver  nitrate  solution,  and  the 
other  with  lead  nitrate  solution.  In  the  presence 
of  phosphorus,  only  the  silver  paper  is  darkened. 

SCHERER  (inosite). — The  aqueous  solution  of  the 
substance  is  evaporated  with  nitric  acid  nearly 
to  dryness,  and  the  residue  is  treated  with 
ammonia'and  with  a  trace  of  calcium  chloride, 
and  again  evaporated.  In  the  presence  of 
inosite,  a  red  coloration  is  obtained. 

SCHERER  (tyrosine). — On  evaporating  a  small 
quantity  of  tyrosine  with  nitric  acid,  a  residue 
which  gives  a  brownish-red  coloration  with 
ammonia  or  sodium  hydroxide,  is  obtained. 

SCHIFF  (uric  acid). — A  solution  of  uric  acid, 
rendered  alkaline,  reduces  silver  nitrate,  giving  a 
black  deposit. 

SCHIFF  (aldehydes).  —  An  aqueous  solution  of 
magenta  (0*025  Per  cent.)  decolorised  with 
sulphur  dioxide  has  its  pink  colour  restored  by 
aldehydes  (see  GAYON). 

SCHIFF  (cholesterol). — On  heating  crystals  of  choles- 
terol with  a  mixture  of  2  parts  of  hydrochloric 
acid  and  i  part  of  ferric  chloride  solution,  a  red 
coloration  is  obtained,  whilst  the  liquid,  when 
evaporated,  leaves  a  violet  residue.  Or,  on 
evaporating  cholesterol  with  nitric  acid  to  dry- 
ness,  the  resulting  residue  gives  a  red  colora- 
tion when  treated  with  a  drop  of  ammonia 
solution. 

168 


REAGENTS  AND   REACTIONS. 

SCHIFF  (dextrose  and  carbohydrates  in  general). — 
Test  papers  are  prepared  by  immersing  strips  of 
filter-paper  in  a  solution  composed  of  equal  parts 
of  glacial  acetic  acid  and  of  xylidine  in  a  little 
alcohol.  These  become  red  when  exposed  to 
the  vapours  produced  by  heating  carbohydrates. 

SCHIFF  (urea] . — When  a  crystal  of  urea  is  treated 
with  i  drop  of  furfural  water  (water  shaken  with 
furfural)  and  with  I  drop  of  hydrochloric  acid,  the 
mixture  becomes  successively  yellow,  green,  blue, 
violet,  and  purple-violet. 

SCHINDELMEISTER  (nicotine). — When  a  trace  of  the 
alkaloid  is  treated  with  a  drop  of  30  per  cent, 
formaldehyde  free  from  formic  acid,  and  the 
mixture  left  for  several  hours  and  then  treated 
with  a  drop  of  nitric  acid,  a  scarlet  or  deep  red 
coloration  is  produced. 

SCHLAGDENHAUFFEN  (alkaloids). — The  reagent  con- 
sists of  a  solution  of  selenious  acid  in  strong 
sulphuric  acid. 

SCHLAGDENHAUFFEN  (differentiation  of  alkaloids 
from  glucosides). — A  mixture  in  equal  parts  of 
tincture  of  guaiacum  and  a  saturated  solution  of 
mercuric  chloride  gives  a  blue  coloration  with 
alkaloids,  but  not  with  glucosides. 

SCHLESINGER  (biliary  pigments  in  urine). — Equal 
parts  of  the  urine  and  of  a  10  per  cent,  solution 
of  zinc  acetate  in  absolute  alcohol  are  shaken,  and 
filtered.  In  the  presence  of  urobilin  a  green 
fluorescence  is  obtained,  which  appears  more 
distinct  when  observed  across  the  cone  of  light 
from  a  lens.  The  presence  of  blood  in  the  urine 
interferes  with  the  test,  but  albumin  does  not 
affect  the  result.  It  is  essential  that  the  reagent 
should  be  freshly  prepared,  and  thoroughly 
shaken. 

SCHLESINGER-HOLT  (blood  in  urine). — Ten  c.c. 
of  the  urine  are  shaken  with  about  i  c.c.  of  acetic 
acid,  and  the  mixture  then  treated  with  about  a 
169 


REAGENTS  AND   REACTIONS. 

third  of  its  volume  of  ether,  and  again  shaken. 
The  ethereal  layer  is  separated,  and  shaken  with 
10  drops  of  absolute  alcohol,  then  allowed  to 
stand,  separated  from  the  alcohol,  and  added  to  a 
benzidine  reagent  freshly  prepared  as  follows  : — 
A  little  of  the  benzidine  is  dissolved  in  2  c.c.  of 
acetic  acid,  and  0*5  c.c.  of  this  solution  is  diluted 
with  2  to  3  c.c.  of  3  per  cent,  hydrogen  peroxide 
solution.  On  shaking  the  ethereal  extract  with 
this  reagent,  a  green  coloration  is  obtained  if  the 
urine  contained  a  small  quantity  of  blood,  or  a 
blue  coloration  if  a  large  amount  was  present. 

SCHLICKUM  (arsenic). — A  solution  of  0-4  grm.  of 
stannous  chloride  in  4  grms.  of  hydrochloric  acid 
is  mixed  with  o-oi  grm.  of  sodium  sulphide,  and 
the  solution  under  examination  is  added  to  the 
mixture.  In  the  presence  of  arsenic,  a  yellow 
ring  of  arsenic  sulphide  is  formed  at  the  zone  of 
contact,  and  the  test  is  capable  of  detecting 
^j  mgrm.  of  arsenic. 

SCHLOSSBERGER  (textile  fibres) . — The  reagent  con- 
sists of  a  solution  of  freshly-prepared  nickelous 
hydroxide  in  strong  ammonia  solution.  It 
dissolves  silk,  but  not  cotton  or  wool. 

SCHMIDT  (oxy doses). — A  5  per  cent,  alcoholic 
solution  of  guaiacum  gives  a  blue  coloration  in 
the  presence  of  oxydases. 

SCHMIDT  (saccharin). — See  PINETTE. 

SCHMIDT  (urobilin  and  hydrobilirubin) . — A  saturated 
aqueous  solution  of  mercuric  chloride  gives  a 
red  coloration  with  hydrobilirubin  and  with 
urobilin,  whilst  with  bilirubin  it  gives  a  green 
coloration. 

SCHMIDT  (dextrose).- — On  heating  an  ammoniacal 
solution  of  lead  acetate  with  urine  containing 
dextrose,  a  brownish-red  precipitate  is  obtained. 

SCHMIDT  (apomorphine). — When  10  c.c.  of  a  solu- 
tion of  apomorphine  hydrochloride  are  shaken 
with  i  c.c.  of  chloroform,  and  with  a  few  drops  of 
170 


REAGENTS  AND  REACTIONS. 

potassium  hydroxide  solution,  the  aqueous  layer 
becomes  violet,  and  the  chloroform  blue. 

SCHNEIDER  (alkaloids). — When  strong  sulphuric 
acid  is  added  to  an  intimate  mixture  of  an  alka- 
loid with  cane  sugar,  various  colorations  are 
produced.  For  example,  morphine  and  codeine 
give  a  purple-red  coloration,  which  changes  to 
greenish-violet,  and  then  to  yellow. 

SCHNEIDER  (bismuth  salts) . — When  a  salt  of  bismuth 
is  heated  with  a  reagent  consisting  of  a  mixture 
of  3  parts  of  tartaric  acid,  i  part  of  stannous 
chloride  and  sufficient  potassium  hydroxide 
solution  to  give  a  clear  liquid,  a  black  precipitate 
is  obtained. 

SCHNEIDER  (colza  oil  in  olive  oil). — One  part  of  the 
oil  is  dissolved  in  2  parts  of  ether,  and  the  solution 
shaken  with  20  drops  of  a  saturated  alkaline 
solution  of  silver  nitrate,  and  left  for  twelve 
hours  in  the  dark.  The  liquid  darkens,  or 
becomes  black,  in  the  presence  of  colza  oil. 

SCHONBEIN  (ozone). — A  solution  of  starch  and 
potassium  iodide  becomes  blue  on  contact  with 
ozone. 

SCHONBEIN  (hydrogen  peroxide). — A  neutral,  or 
slightly  acid  solution  of  hydrogen  peroxide,  gives 
a  blue  coloration,  on  treatment  with  ferrous 
sulphate  and  a  solution  of  zinc  iodide  and 
starch. 

SCHONBEIN-PAGENSTECKER  (hydrocyanic  acid)  .— 
Strips  of  filter-paper  are  dipped  in  guaiacum 
tincture,  and  then  dried,  and  dipped  in  o-i  per 
cent,  copper  sulphate  solution.  They  turn  blue 
on  contact  with  hydrocyanic  acid.  The  reaction 
is  also  given  by  ozone  and  other  oxidising 
agents. 

SCHRYVER  (formaldehyde). — Ten  c.c.  of  the  liquid 
under  examination  are  treated  with  2  c.c.  of  a 
recently-prepared  and  filtered  i  per  cent,  solution 
of  phenylhydrazine  hydro  chloride,  i  c.c,  of 


REAGENTS  AND  REACTIONS. 

freshly-prepared  5  per  cent,  solution  of  potas- 
sium ferricyanide,  and  5  c.c.  of  strong  hydro- 
chloric acid.  In  the  presence  of  formaldehyde, 
a  red  coloration  is  obtained.  Sensitiveness  = 
i  :  1,000,000. 

SCHUCHARDT  (free  hydrochloric  acid  in  gastric  juice) . 
— See  VON  DER  VELDEN. 

SCHULTZ  (salicylic  acid). — An  aqueous  solution  of 
salicylic  acid,  when  treated  with  a  small  quantity 
of  copper  sulphate  solution,  gives  a  green  colora- 
tion, which  disappears  on  the  addition  of 
ammonia  or  mineral  acids. 

SCHULTZE  (alkaloids). — The  reagent  is  a  solution  of 
phospo-antimonic  acid,  prepared  by  mixing 
4  parts  of  a  saturated  solution  of  sodium  phos- 
phate with  i  part  of  antimony  chloride.  It 
gives  white  precipitates  with  most  alkaloids. 

SCHULTZE  (cellulose). — A  solution  of  250  grms.  of 
zinc  chloride  and  80  grms.  of  potassium  iodide  in 
85  c.c.  of  water,  saturated  with  iodine,  gives  a 
blue  coloration  with  cellulose. 

SCHULTZE  (solution  for  microscopy).  --  (i)  An 
aqueous  i  per  cent,  solution  of  osmic  acid.  (2)  A 
solution  of  o-i  to  0-3  grm.  of  palladium  chloride 
in  100  c.c.  of  water. 

SCHULTZE  (proteins). — A  solution  of  the  substance 
in  sulphuric  acid  is  mixed  with  a  trace  of  sugar, 
and  heated  to  60°  C.  In  the  presence  of  pro- 
teins a  bluish-red  coloration  is  produced. 

SCHULZ  (carbon  monoxide  in  blood). — See  WETZEL. 

SCHUMPELITZ  (veratrine). — On  mixing  a  solution 
of  fused  zinc  chloride  in  dilute  hydrochloric  acid 
with  a  few  drops  of  a  salt  of  veratrine,  and 
allowing  the  liquid  to  evaporate,  a  red  coloration 
is  produced. 

SCHUYTEN    (nitrous    acid). — The    reagent    is    pre- 
pared by  diluting  10  c.c.  of  a  solution  of  i  part 
of  antipyrin  in   10  parts  of  acetic  acid  with 
10  c.c.  of  water.    On  treating  5  c.c.  of  the  liquid 
172 


REAGENTS  AND   REACTIONS. 

under  examination  with  5  c.c.  of  the  reagent,  the 
formation  of  a  green  coloration  indicates  the 
presence  of  nitrous  acid  (see  CURTMANN). 

SCHWARZ  (sulphonal). — Sulphonal,  when  heated  on 
charcoal,  emits  an  odour  of  mercaptan. 

SCHWARZ  (chloroform). — When  chloroform  is  heated 
with  resorcinol  and  alcoholic  potassium  hydroxide 
solution,  the  liquid  becomes  reddish- yellow,  and 
sometimes  shows  a  green  fluorescence. 

SCHWEITZER  (textile  fibres). — The  reagent  is  a  con- 
centrated solution  of  freshly-precipitated  and 
still  moist  copper  hydroxide  in  20  per  cent, 
ammonia  solution.  It  dissolves  cotton,  linen 
and  silk,  but  not  wool. 

SEIDEL  (inosite). — The  liquid  under  examination 
is  evaporated  with  nitric  acid,  and  the  residue 
is  treated  with  a  solution  of  strontium  acetate. 
The  presence  of  inosite  is  indicated  by  the 
appearance  of  a  violet  coloration. 

SELIWANOFF  (Icevulose). — When  laevulose  is  heated 
with  resorcinol  and  hydrochloric  acid  it  gives  a 
red  coloration,  and  then  a  red  precipitate  soluble 
in  alcohol. 

SELMI  (coniine  and  nicotine}. — An  aqueous  solution 
of  these  alkaloids  gives  a  black  precipitate  with 
potassium  sulphoplatinite.  In  the  presence  of 
50  per  cent,  acetic  acid  the  reaction  is  given  only 
by  nicotine,  and  not  by  coniine. 

SELMI  (blood). — The  reaction  is  based  on  the 
separation  of  crystals  of  haemin  by  means  of 
sodium  tungstate  and  acetic  acid. 

SENIER-LOWE  (glycerin). — When  a  borax  bead  is 
moistened  with  a  liquid  containing  glycerin, 
and  heated  in  a  gas  flame,  it  becomes  green. 

SILVA  (FERREIRA  DA)  (cocaine). — On  evaporating 
cocaine  to  dryness  with  fuming  nitric  acid,  and 
adding  to  the  residue  2  drops  of  a  saturated 
alcoholic  solution  of  potassium  hydroxide,  an 
odour  of  peppermint  is  developed. 
173 


REAGENTS  AND   REACTIONS. 

SILVA  (FERREIRA  DA)  (eserine). — On  dissolving  a 
small  quantity  of  eserine  or  one  of  its  salts  in 
fuming  nitric  acid,  there  is  obtained  a  clear 
yellow  solution,  which  becomes  orange-red  when 
heated,  and,  evaporated  on  the  water-bath, 
leaves  a  green  residue.  This  residue  is  soluble  in 
water  and  in  alcohol,  and,  when  treated  with 
nitric  acid,  gives  a  solution  with  a  greenish- 
yellow  and  blood-red  fluorescence. 

SIMON  (acet aldehyde). — A  very  dilute  solution  of 
acetaldehyde  (as  weak  as  o-oooi  per  cent.), 
when  treated  with  an  aqueous  solution  of 
trimethylamine  and  with  a  very  dilute  solution 
of  sodium  nitroprusside  until  coloured,  gives  a 
blue  coloration.  The  same  reaction  is  given  by 
phenylhydrazine  when  heat  is  applied.  On 
adding  potassium  hydroxide,  the  colour  is 
intensified,  whilst,  on  the  addition  of  acetic  acid, 
it  is  changed  to  bright  blue. 

SKEY  (salts  of  cobalt}. — When  a  solution  of  a 
cobalt  salt  is  treated  with  tartaric  or  citric  acid, 
and  then  with  an  excess  of  ammonia  and  with 
potassium  ferri cyanide,  it  gives  a  deep  red 
coloration. 

SMITH  (biliary  pigments  in  urine). — One  drop  of 
tincture  of  iodine  is  added  to  the  urine.  In  the 
presence  of  biliary  pigments,  a  green  coloration 
is  produced.  Ferric  chloride,  lead  peroxide,  and 
hydrogen  peroxide  act  in  the  same  way  as 
iodine. 

SOLDAINI  (dextrose). — The  reagent  consists  of  a 
solution  of  15  grms  of  copper  carbonate,  and 
416  grms.  of  potassium  bicarbonate  in  1,000 
c.c.  of  water.  When  boiled  with  dextrose 
or  lactose,  it  yields  a  red  deposit  of  cuprous 
oxide. 

SOLTSIEN   (sesame  oil). — Six  grms.  of  the  oil  are 
heated  with  2  c.c.  of  Bettendorfs  reagent  on 
the  water-bath  for  some  minutes,  with  constant 
174 


REAGENTS  AND   REACTIONS. 

agitation.  The  stannous  chloride  solution  be- 
comes of  an  intense  wine-red  colour  when 
sesame  oil  is  present.  Sensitiveness  =  i  :  100. 

SONNENSCHEIN  (alkaloids). — (i)  Phosphomolybdic 
acid  gives  yellow  precipitates  with  slightly  acid 
solutions  of  alkaloids.  The  reagent  is  prepared 
by  treating  a  nitric  acid  solution  of  ammonium 
molybdate  with  phosphoric  acid,  washing  the 
precipitate,  boiling  it  with  aqua  regia  until  the 
ammonium  salt  is  completely  decomposed,  and 
evaporating  the  solution  to  dryness.  The 
residue  is  then  dissolved  in  10  per  cent,  nitric 
acid. 

(2)  Another  reagent  for  alkaloids  is  prepared 
by  passing  a  current  of  chlorine  into  a  solution 
of  an  alkali,  in  which  is  suspended  cerous 
hydroxide,  until  brown  cerium  oxide  is  obtained. 
This  is  collected  on  a  filter,  and  dried.  The 
reagent  is  used  by  dissolving  the  alkaloid  in 
strong  sulphuric  acid,  and  treating  the  solution 
with  a  trace  of  cerium  oxide.  Under  these 
conditions  atropine  gives  a  brownish-yellow 
coloration,  quinine  a  yellow;  codeine,  olive- 
green  ;  emetine,  brown  ;  narcotine,  first  brown 
and  then  cherry-red ;  strychnine,  blue,  then 
violet,  and  finally  cherry-red  ;  and  veratrine,  a 
brownish-red  coloration. 

SONNENSCHEIN  (blood). — A  dilute  filtered  solution 
of  blood  gives,  with  phosphotungstic  acid,  a 
voluminous  brownish-red  precipitate,  which  is 
soluble  in  ammonia,  forming  an  intense  red 
solution.  This  solution  shows  the  spectrum  of 
reduced  methaemoglobin. 

SPIEGLER  (albumin  in  urine). — The  reagent  con- 
sists of  8  grms.  of  mercuric  chloride,  4  grms.  of 
tartaric  acid,  and  20  grms.  of  sugar  in  200  c.c. 
of  water.  When  added  to  albuminous  urine,  a 
white  ring  is  fomred  at  the  zone  of  contact  of  the 
two  liquids.  Sensitiveness  =  i  :  225,000. 
175 


REAGENTS  AND   REACTIONS. 

SPRENGEL  (nitric  acid}. — The  substance  under 
examination  is  treated  with  2  drops  of  a  solution 
of  i  part  of  phenol  in  4  parts  of  strong  sulphuric 
acid  and  2  parts  of  water.  In  the  presence  of 
nitric  acid,  there  is  produced  a  pink-brown 
coloration,  which  changes  to  yellow  on  the  addi- 
tion of  ammonia. 

STAHRE  (citric  acid). — When  a  solution  of  free 
citric  acid,  or  of  a  citrate,  in  very  dilute  sulphuric 
acid  is  gradually  heated  with  2  to  5  drops  of 
N-io  potassium  permanganate  solution  to 
30° — 40°  C.,  a  brown  coloration  is  obtained.  On 
now  adding  i  to  2  drops  of  ammonium  oxalate 
solution,  and  about  i  c.c.  of  10  per  cent,  sul- 
phuric acid,  the  liquid  becomes  clear  again,  and, 
on  then  treating  it  with  a  few  drops  of  bromine, 
a  crystalline  precipitate  of  tetrabromo-acetone 
will  be  formed.  Sensitiveness  =  0*3  mgrm.  in 
i  c.c.  of  water. 

STENHOUSE  (caffeine). — When  caffeine  is  heated 
for  a  few  minutes  with  nitric  acid,  the  solution 
evaporated,  and  the  residue  moistened  with 
ammonia,  a  purple-red  coloration,  which 
becomes  fainter  on  the  addition  of  potassium 
hydroxide  solution,  is  obtained. 

STOCKWIS  (biliary  pigments  in  urine). — Thirty  c.c. 
of  the  urine  are  treated  with  10  c.c.  of  a  20  per 
cent,  solution  of  zinc  chloride,  the  zinc  precipi- 
tated with  sodium  carbonate,  and  the  washed 
precipitate  dissolved  in  ammonia  solution.  In 
the  presence  of  biliary  pigments,  the  solution  will 
be  of  a  green  colour  and  fluorescent. 

STORCH  (unboiled  and  boiled  milk). — See  SCHAFFER. 

STORCH-MORAWSKI  (resin  oils  and  resins  in  oils). — 
A  small  quantity  of  the  oil  under  examination  is 
dissolved  in  warm  acetic  anhydride,  and  the 
solution,  when  cold,  is  treated  with  a  few  drops 
of  sulphuric  acid.  In  the  presence  of  resin  oils, 
or  resins,  violet-blue  or  red  colorations  are 
176 


REAGENTS  AND   REACTIONS. 

produced,  and,  finally,  the  solution  becomes 
fluorescent  brownish-yellow. 

STROPPA  (solanine). — On  treating  a  little  solanine 
in  a  porcelain  basin  with  2  drops  of  a  dilute 
solution  of  potassium  iodide  and  2  c.c.  of  dilute 
sulphuric  acid  (1:7),  and  heating  the  mixture, 
with  agitation,  to  75°  to  80°  C.  on  the  water-bath, 
it  becomes  successively  yellow,  red,  violet,  blue, 
and  finally  green. 

STRUVE  (blood  in  urine). — The  urine  is  treated  with 
ammonia,  and  then  with  tannin  and  acetic  acid, 
until  the  reaction  becomes  acid.  In  the  presence 
of  blood,  a  red  precipitate  is  formed,  and  this 
when  dried  and  treated  with  acetic  acid  and 
sodium  chloride  yields  characteristic  haemin 
crystals. 

STRZYOWSCKY  (albumin  in  urine). — Ten  c.c.  of  the 
urine  are  treated  with  a  little  10  per  cent, 
ammonium  persulphate  solution.  In  the  pre- 
sence of  albumin,  a  greyish- white  ring  is  formed 
at  the  zone  of  contact  of  the  liquids. 

SWOBODA  (picric  acid}. — On  treating  a  cold  aqueous 
solution  of  picric  acid  with  an  aqueous  solution 
of  methylene-blue  there  is  formed  a  violet 
precipitate,  which  dissolves  in  chloroform,  to 
form  a  blue  solution,  and  this,  when  evaporated, 
leaves  a  violet  residue. 

SZANKAY  (cocaine}. — When  cocaine  is  triturated 
with  iodol  it  emits  a  pleasant  odour,  recalling 
that  of  hyacinth. 

T. 

TAFEL  (strychnine}. — When  a  solution  of  o-i  grm. 
of  strychnine  sulphate  in  10  c.c.  of  water  is 
treated  with  2  drops  of  water,  4  drops  of  hydro- 
chloric acid,  and  an  excess  of  zinc  powder, 
reduction  of  the  strychnine  takes  place,  with 
the  formation  of  tetrahydrostrychnine  and 

R.R.  177  12 


REAGENTS  AND   REACTIONS. 

strychnidine.  If  the  liquid  is  then  heated  and  fil- 
tered, and  the  filtrate  treated  with  a  drop  of  ferric 
chloride  solution,  a  blood- red  coloration,  which 
does  not  disappear  on  heating,  is  obtained. 

TAMBON  (sesame  oil  in  olive  oil). — Five  c.c.  of 
colourless  nitric  acid  (i  :  10)  are  shaken  for  two 
minutes  with  15  c.c.  of  the  oil,  and  the  mixture 
allowed  to  stand.  In  the  presence  of  sesame 
oil,  the  acid  layer  becomes  yellow,  and,  when 
separated  by  decantation  and  treated  with  a 
sufficient  quantity  of  water,  becomes  more  or 
less  turbid.  In  the  case  of  pure  sesame  oil  a 
white  flocculent  precipitate  is  obtained. 

TANRET  (albumin  in  urine}. — The  reagent  consists  of 
3-32  grms.  of  potassium  iodide  and  1-35  grms.  of 
mercuric  chloride  in  20  c.c.  of  acetic  acid  and 
60  c.c.  of  water.  When  added  in  sufficient 
quantity  to  albuminous  urine,  it  gives  a  white 
precipitate.  Alkaloids  also  give  a  precipitate, 
which,  however,  is  soluble  in  ether.  The  albu- 
min precipitate  is  insoluble  in  hot  acetic  acid, 
whereas  the  precipitate  given  by  any  peptones 
present  is  soluble  therein. 

TATTERSALL  (salts  of  cobalt). — On  treating  a  solu- 
tion of  a  cobalt  salt  with  potassium  cyanide 
solution  until  the  precipitate  first  formed  is  re- 
dissolved,  and  then  adding  ammonium  sulphide, 
a  blood-red  coloration  is  produced.  This  reac- 
tion takes  place  in  the  presence  of  nickel  salts, 
but  copper  salts  interfere  with  it. 

TATTERSALL  (morphine).  --  When  morphine  is 
treated  with  strong  sulphuric  acid  and  sodium 
arsenate,  the  mixture  becomes  dirty  violet  and 
then  sea-green. 

TATTERSALL  (papaverine  and  codeine). — The  sub- 
stance is  heated  with  a  little  strong  sulphuric 
acid,  sodium  arsenate  then  added,  and  the  heating 
continued  over  a  low  flame,  with  stirring.  In  the 
presence  of  papaverine,  there  is  produced  a  bright 


REAGENTS  AND   REACTIONS. 

red  to  violet  coloration,  which  changes  to  yellow 
on  the  addition  of  10  c.c.  of  water,  and  to  black 
when  sodium  hydroxide  is  subsequently  added. 
Codeine,  under  the  same  conditions,  gives  a  deep 
blue  coloration,  which  changes  to  orange  when 
treated  with  water  and  sodium  hydroxide. 

TEICHMANN  (blood). — -The  substance  under  exami- 
nation is  treated  with  glacial  acetic  acid  and  a 
trace  of  sodium  chloride,  and  gently  heated 
several  times  until  bubbles  appear.  In  the 
presence  of  blood,  the  characteristic  crystals  of 
haemin  separate. 

THEATER  (santonine). — When  santonine  is  treated 
with  2  to  3  drops  of  a  2  per  cent,  alcoholic  solu- 
tion of  furfural,  and  then  with  2  c.c.  of  strong 
sulphuric  acid,  and  the  mixture  is  heated  on 
the  water-bath  until  the  alcohol  evaporates,  a 
purple-red  coloration,  changing  to  carmine-red 
and  then  to  blue,  is  produced.  Sensitiveness  = 
o-i  mgrm. 

THENARD  (aluminium  .salts). — Aluminium  salts, 
when  heated  for  some  time  on  charcoal,  and  then 
moistened  with  cobalt  nitrate,  yield  a  fused  mass 
of  blue  colour. 

THERENON  (formaldehyde). — Metol  gives  a  garnet- 
red  coloration  with  formaldehyde.  The  reaction 
is  promoted  by  a  gentle  heat,  not  exceeding 
75°  C. 

THOMS  (dulcine). — On  treating  a  small  quantity  of 
dulcine  with  2  to  3  drops  of  pure  phenol,  and  with 
the  same  quantity  of  strong  sulphuric  acid,  and 
then  heating  the  mixture  to  boiling  point,  a  red 
syrup  is  obtained.  When  this  is  introduced  into 
a  test-tube  half  full  of  water,  and  the  liquid 
completely  cooled  and  treated  with  sodium 
hydroxide  or  ammonia,  two  layers  are  formed, 
on  the  edges  of  which  a  blue  ring  immediately 
appears. 

THOMSON  (veratrine). — Strong  sulphuric  acid  gives 

179  12—2 


REAGENTS  AND   REACTIONS. 

a  blood-red  coloration  with  veratrine  after  about 
four  minutes. 

THORMAHLEN  (melanine  in  urine). — The  urine  is 
treated  with  sodium  nitroprusside,  potassium 
hydroxide,  and  acetic  acid,  and,  in  the  presence  of 
melanine,  gives  a  deep  blue  coloration. 

TOCHER  (sesame  oil  in  olive  oil). — (i)  Ten  c.c.  of 
formaldehyde  (40  per  cent.)  are  mixed  with 
50  c.c.  of  water,  and  100  c.c.  of  sulphuric  acid. 
On  mixing  5  c.c.  of  this  reagent  with  5  c.c.  of  the 
oil,  the  resulting  emulsion  becomes  a  permanent 
blackish-blue  if  sesame  oil  is  present. 

(2)  Fifteen  c.c.  of  the  oil  are  shaken  with  a 
solution  of  i  grm.  of  pyrogallol  in   14  c.c.  of 
hydrochloric  acid,  and  the  acid  layer  is  sepa- 
rated, and  heated  for  a  few  minutes.     In  the 
presence  of  sesame  oil,   a  violet   coloration   is 
obtained. 

(3)  When  2  c.c.  of  sesame  oil  are  shaken  with 
2  c.c.  of  a  saturated  solution  of  resorcinol  in 
petroleum  spirit,  and  2  c.c.  of  strong  nitric  acid, 
a  violet-blue  coloration  is  obtained. 

(4)  On   shaking   sesame   oil   with   a   reagent 
consisting  of  4  grms.  of  ammonium  vanadate  in 
50  c.c.  of  water  and  100  c.c.  of  strong  sulphuric 
acid,  a  green  coloration  is  produced. 

TODTENHAUPT  (formaldehyde). — When  a  dilute 
solution  of  ammonium  sulphide  is  treated  with  a 
little  formaldehyde,  a  turbidity  is  obtained,  and, 
on  the  further  addition  of  the  aldehyde,  a  fine 
crystalline  precipitate  gradually  forms. 

TOLLENS  (dextrose). — A  solution  of  silver  nitrate  is 
treated  with  potassium  hydroxide,  and  then  with 
sufficient  ammonia  to  redissolve  the  precipitate 
first  formed.  This  reagent  is  reduced  by  dextrose, 
and  gives  a  black  coloration. 

TOLLENS  (pentoses). — Pentoses  give  a  cherry-red 
coloration  when  heated  with  strong  hydrochloric 
acid  and  phloroglucinol. 
1 80 


REAGENTS  AND   REACTIONS. 

TOMMASI  (phenol). — See  HOPPE-SEYLER. 

TOPPER  (hydrochloric  acid  in  gastric  juice). — The 
reagent  consists  of  a  solution  of  dimethylamino- 
azobenzene,  which  gives  a  red  coloration  with 
free  or  combined  hydrochloric  acid. 

TORTELLI-PIAZZA  (saccharin). — When  saccharin  is 
heated  with  magnesium  powder,  it  yields  mag- 
nesium sulphide,  which  gives  a  violet  coloration 
with  sodium  nitroprusside. 

TORTELLI-RUGGERI  (cotton  oil). — The  liquid  fatty 
acids  of  the  oil  are  separated,  and  from  5  to 
6  grms.  thereof  are  dissolved  in  10  c.c.  of  pure 
99  per  cent,  alcohol.  The  solution  is  treated  with 
i  c.c.  of  a  5  per  cent,  aqueous  solution  of  silver 
nitrate,  and  the  mixture  is  heated  on  the  water- 
bath  at  70°  to  80°  C.  In  the  case  of  pure  cotton 
oil,  there  is  produced  immediately  a  reddish 
coloration,  which  soon  changes  to  brownish-red, 
whilst  the  liquid  becomes  turbid,  and  appears 
violet-blue  by  transmitted  light.  Oils  free  from 
cotton  oil  do  not  show  any  coloration  after 
thirty  minutes,  whilst  mixtures  containing  i  per 
cent,  or  more  of  cotton  oil  soon  show  a  deep 
brown  coloration. 

TORTI  (resorcinol). — On  heating  a  crystal  of 
resorcinol  with  a  few  drops  of  nitric  acid  (sp.  gr. 
1-40)  an  intense  red  coloration  is  produced. 
Sensitiveness  =  0-25  mgrm. 

TRAPP  (veratrine}. — A  permanent  purple-red  colora- 
tion is  obtained  on  heating  veratrine  with 
strong  hydrochloric  acid. 

TRILLAT  (formaldehyde}. — The  liquid  under  exami- 
nation is  heated  with  dimethylaminiline  and 
sulphuric  acid,  and  then  made  alkaline,  and 
freed  from  the  excess  of  dimethylaniline  by 
means  of  a  current  of  steam,  followed  by  filtration. 
On  moistening  the  filter  with  acetic  acid,  and 
adding  lead  dioxide,  a  violet  coloration  is  pro- 
duced. 

181 


REAGENTS  AND   REACTIONS. 

TROMMER  (dextrose  in  urine}. — The  urine,  when 
heated  with  copper  sulphate  and  sodium 
hydroxide,  gives  a  precipitate,  which  redissolves 
on  heating,  forming  a  blue  solution,  which 
changes  to  red  on  the  precipitation  of  cupric 
hydroxide. 

TROMMSDORF  (nitrous  acid}. — Five  grms.  of  zinc 
chloride  are  dissolved  in  100  c.c.  of  water, 
and  the  solution  is  mixed  with  5  grms.  of  starch, 
and  boiled  until  the  starch  has  dissolved,  the 
water  which  evaporates  being  renewed  from  time 
to  time.  Two  grms.  of  zinc  iodide  are  then 
added,  and  the  solution  is  made  up  to  a  litre, 
and  filtered.  On  adding  this  reagent  to  a  liquid 
containing  nitrous  acid,  an  intense  blue  colora- 
tion is  obtained. 

TRUCHOT  (artificial  silk}. — A  little  of  the  material 
is  dissolved  in  sulphuric  acid  (66°  Be.),  and  a 
crystal  of  diphenylamine  dissolved  in  strong 
sulphuric  acid  is  added  to  the  syruppy  solution. 
Under  these  conditions,  natural  silk  remains 
colourless,  whilst  artificial  silk  (nitrocellulose) 
produces  a  blue  coloration. 

TSCHUGAEFF  (salts  of  nickel} . — The  solution  under 
examination  is  treated  with  ammonia  until  the 
reaction  is  slightly  alkaline,  and  then  with  i  to 
2  c.c.  of  a  i  per  cent,  alcoholic  solution  of  dime- 
thylglyoxime.  In  the  presence  of  nickel,  a  red 
precipitate  separates  on  boiling  the  liquid. 
Sensitiveness  —  i  :  400,000. 

U. 

UDRANSKY  (biliary  acids  in  urine}. — Five  c.c.  of 
the  urine  are  treated  with  5  drops  of  a  o-i  per 
cent,  aqueous-solution  of  furfural,  and  then  with 
5  c.c.  of  sulphuric  acid,  while  kept  cold.  In  the 
presence  of  biliary  acids,  a  red  coloration  is 
produced. 

182 


REAGENTS  AND   REACTIONS. 

UDRANSKY  (cholesterol}. — When  a  mixture  of  10  c.c. 
of  an  alcoholic  solution  of  cholesterol,  and  of  5 
drops  of  a  0-5  per  cent,  aqueous  solution  of 
furfural,  is  treated  with  5  c.c.  of  strong  sulphuric 
acid  in  such  a  way  that  the  liquids  do  not  mix, 
and  is  then  cooled,  and  gently  shaken,  there  is 
produced  an  intense  red  coloration,  which  changes 
to  blue. 

UDRANSKY  (phenol  and  paracresol). — On  treating 
5  c.c.  of  an  aqueous  solution  of  phenol  with  5 
drops  of  a  0-5  per  cent,  aqueous  solution  of 
phenol  and  5  c.c.  of  strong  sulphuric  acid,  the 
mixture  becomes  bluish-red  or  blue.  A  solution 
of  paracresol,  under  the  same  conditions,  gives  a 
bright  red  coloration,  changing  to  violet  and  then 
to  blue. 

UDRANSKY  (dextrose  in  urine). — From  2  to  3  c.c. 
of  the  urine  are  treated  with  5  drops  of  a  15  per 
cent,  solution  of  a-naphthol,  and  then  with 
5  c.c.  of  strong  sulphuric  acid.  In  the  presence 
of  dextrose,  a  violet  ring  is  formed  at  the  zone  of 
contact,  whilst  the  liquid,  when  shaken,  becomes 
carmine-red. 

UDRANSKY  (scatol). — On  treating  a  solution  of 
scatol  with  a  drop  of  a  2  per  cent,  aqueous 
solution  of  furfural,  and  with  strong  sulphuric 
acid,  a  brownish-red  coloration  is  obtained. 

UDRANSKY  (tyrosine). — When  an  aqueous  solution 
of  tyrosine  is  treated  with  a  few  drops  of  aqueous 
furfural,  and  with  an  equal  volume  of  strong 
sulphuric  acid,  and  then  cooled,  a  pale  red 
mixture  is  obtained. 

UFFELMANN  (lactic  acid  in  gastric  juice). — The 
reagent  consists  of  a  mixture  of  I  drop  of  ferric 
chloride  solution  with  a  solution  of  0-4  grm.  of 
phenol  in  100  c.c.  of  water.  In  the  presence  of 
lactic  acid,  it  gives  a  yellow  coloration. 

UFFELMANN  (coriander  in  flour). — On  heating  the 
flour  with  a  dilute  alcoholic  solution  of  sodium 

183 


REAGENTS  AND   REACTIONS. 

hydroxide,  a  yellow  coloration,  changing  to  red, 

is  obtained. 
ULTZMANN     (biliary     pigments    in     urine). — See 

GMELIN. 
UTZ    (blood). — An    alkaline    solution    of    phenol- 

phthalein,   decolorised  by  reduction  with  zinc 

powder,  becomes  pink   again  on  contact  with 

hydrogen  peroxide  and  blood. 


V. 

VALSER  (alkaloids). — The  reagent  consists  of  a 
10  per  cent,  aqueous  solution  of  potassium  iodide 
saturated  with  mercuric  iodide. 

VANINO-SEEMANN  (hydrogen  peroxide). — Hydrogen 
peroxide  in  alkaline  solution  immediately  pre- 
cipitates gold,  in  a  fine  state  of  division,  from 
solutions  of  gold  salts.  The  precipitate  appears 
blackish-brown  by  reflected  light,  and  blue-green 
by  transmitted  light.  Sensitiveness  =  0-03  mgrm. 
of  gold  in  10  c.c.  of  liquid. 

VELDEN  (VAN  DER)  (hydrochloric  acid  in  gastric 
juice). — A  yellow  aqueous  or  alcoholic  solution 
of  tropseolin  OO  gives  a  bright  red,  or  brown-red 
coloration  with  hydrochloric  acid. 

VILLAVECCHIA-FABRIS  (sesame  oil  in  olive  oil). — 
From  5  to  10  c.c.  of  the  oil  are  added  to  2  to  3 
drops  of  a  2  per  cent,  alcoholic  solution  of  fur- 
fural, and  the  mixture  is  shaken  for  a  few  seconds 
with  10  c.c.  of  strong  hydrochloric  acid,  and 
allowed  to  stand.  In  the  presence  of  as  little  as 
i  per  cent,  of  sesame  oil,  the  lower  acid  layer  will 
be  of  a  reel  colour,  which  becomes  more  pro- 
nounced on  standing,  whilst  the  upper  oily  layer 
will  appear  as  a  yellowish  emulsion  mixed  with 
red. 

VITAL:  (biliary  acids  in  urine). — A  small  quantity 
of  the  liquid  under  examination  is  treated  with 
184 


REAGENTS   AND   REACTIONS. 

strong  sulphuric  acid  until  it  dissolves,  and  a  few 
drops  of  chlorine  water  are  added  in  such  a  way 
that  the  liquids  do  not  mix.  After  a  few  seconds, 
if  biliary  acids  are  present,  green  streaks  will 
appear  at  the  zone  of  contact,  the  colour  then 
changing  to  blue,  violet,  and  red.  On  adding  a 
large  amount  of  sulphuric  acid  to  the  liquid,  a 
green  fluorescence  will  be  observed. 

VITALI  (alkaloids). — When  alkaloids  are  evaporated 
with  fuming  nitric  acid  on  the  water-bath,  and 
the  residue  is  treated  with  i  drop  of  an  alcoholic 
solution  of  potassium  hydroxide,  various  colora- 
tions are  produced.  Atropine,  for  example, 
gives  a  violet  coloration. 

VITALI  (aniline). — On  treating  aniline  with  strong 
sulphuric  acid,  in  which  is  dissolved  a  crystal  of 
potassium  chlorate,  a  violet  coloration,  which  is 
intensified  by  the  addition  of  a  little  water,  is 
obtained. 

VITALI  (chloroform). — When  chloroform  is  heated 
with  a  fragment  of  sodium  hydroxide  and  a  little 
thymol,  a  fine  violet  coloration  is  produced. 

VITALI  (iodoform). — A  red  coloration  is  obtained 
by  mixing  iodoform  with  phenol  and  potassium 
hydroxide  solution,  and  heating  the  mixture  to 
boiling  point. 

VITALI  (hydrastine). — On  treating  hydrastine  with 
a  few  drops  of  nitric  acid,  a  yellow  coloration  is 
produced,  and  on  now  heating  the  mixture  to 
boiling  point,  and  then  evaporating  the  acid  at  a 
gentle  heat,  a  yellow  residue  is  left.  This  becomes 
brown  on  the  addition  of  alcoholic  potassium 
hydroxide  solution,  and  the  liquid,  when  evapor- 
ated to  dryness,  leaves  a  brown  residue,  which 
becomes  intense  violet  on  the  addition  of  strong 
sulphuric  acid. 

VITALI  (sulphonal). — When  sulphonal  is  heated 
with  three  times  its  volume  of  potassium 
hydroxide  solution  it  emits  a  garlic  odour,  and 

185 


REAGENTS  AND   REACTIONS. 

the  solution  on  cooling  becomes  scarlet,  changing 
to  blue  on  the  addition  of  water.  On  then  adding 
hydrochloric  acid,  an  odour  of  sulphur  dioxide 
is  evolved,  and  the  colour  becomes  violet. 

VITALI  (acetone). — When  acetone  is  shaken  with  a 
drop  of  potassium  hydroxide  solution  and  a 
little  carbon  bisulphide,  and  a  crystal  of  ammo- 
nium molybdate  and  an  excess  of  sulphuric 
acid  then  added,  a  wine-red  coloration  is 
produced. 

VITALI-MAHLER  (saccharin). — When  saccharin  is 
fused  with  a  fragment  of  metallic  sodium  or 
potassium,  it  is  converted  into  an  alkali  sulphide, 
which  gives  the  well-known  violet  coloration  with 
sodium  nitroprusside. 

VOGEL  (narceine). — The  substance  is  moistened 
with  chlorine  water,  and  shaken  with  a  drop  of 
ammonia  solution.  If  narceine  is  present,  a 
deep-red  coloration  is  obtained. 

VOGEL  (salts  of  cobalt). — On  treating  a  neutral  or 
slightly-acid  (acetic  acid)  solution  of  a  cobalt 
salt  with  a  strong  solution  of  ammonium 
thiocyanate,  a  bright  blue  solution  is  obtained. 
If  this  is  shaken  with  a  mixture  of  i  volume  of 
amyl-alcohol  and  10  to  15  volumes  of  ether,  the 
supernatant  amyl  alcohol  becomes  blue.  Sensi- 
tiveness =  0-02  mgrm.  of  cobalt. 

VORTMANN  (hydrocyanic  acid). — When  a  liquid 
containing  hydrocyanic  acid  is  heated  to  boiling 
point  with  a  few  drops  of  potassium  nitrite  solu- 
tion, 2  to  4  drops  of  ferric  chloride  solution,  and 
i  drop  of  sulphuric  acid,  then  cooled,  treated  with 
ammonia  and  filtered,  and  the  filtrate  treated 
with  ammonium  sulphide,  a  violet  coloration, 
due  to  the  formation  of  sodium  nitroprusside,  is 
obtained. 

VOURNASOS  (lactic  acid  in  gastric  juice). — Five  c.c. 
of  the  filtered  gastric  juice  are  rendered  strongly 
alkaline  with  10  per  cent,  potassium  hydroxide 
186 


REAGENTS  AND 

solution,  boiled  for  ten  minutes,  and  treated  with 
i  to  2  c.c.  of  a  reagent  prepared  by  dissolving 
i  grm.  of  iodine,  and  0-5  grm.  of  potassium  iodide 
in  50  c.c.  of  water,  filtering,  and  adding  5  grms. 
of  methylamine  to  the  filtrate.  In  the  presence 
of  lactic  acid  (down  to  0-005  Per  cent.),  the 
unpleasant  odour  of  isonitrile  is  emitted. 
VULPIUS  (sulphonal). — When  sulphonal  is  heated 
with  potassium  cyanide  the  odour  of  mercaptan 
is  evolved,  and  on  treating  the  fused  mass  with 
water,  and  adding  ferric  chloride  solution,  a 
blood-red  coloration  will  be  obtained. 


W. 

WAGNER-FRESENIUS  (alkaloids). — This  is  the  well- 
known  reaction  with  a  solution  of  potassium  and 
mercuric  iodides. 

WANGERIN  (narcotine). — A  solution  of  o-oi  grm.  of 
the  substance  in  20  drops  of  strong  sulphuric  acid 
is  heated  with  i  or  2  drops  of  a  i  per  cent,  solu- 
tion of  cane  sugar,  in  a  watch-glass,  on  the  water- 
bath.  In  the  presence  of  narcotine  there  is 
produced  a  greenish- yellow  coloration,  which 
changes  successively  to  yellow,  brownish- yellow, 
brown,  violet-brown,  and  finally  to  brilliant 
violet-blue.  Only  this  last  coloration  is  dis- 
tinctive of  narcotine,  since  all  the  alkaloids  react 
with  strong  sulphuric  acid,  giving  similar  colora- 
tions. 

WANGERIN  (hydrastine). — When  hydrastine  is 
heated  on  the  water-bath  with  sulphuric  acid  and 
tannin,  it  gives  a  green  coloration,  which,  when 
the  mixture  is  cooled  and  again  heated,  changes 
to  blue  and  then  to  dirty  green,  and  finally  yields 
a  blackish  precipitate. 

WAUTHERS  (saccharin). — When  a  small  quantity 
of  saccharin  is  heated  with  strong  sulphuric  acid 

187 


REAGENTS  AND   REACTIONS. 

and   resorcinol,    a  violet   coloration,   which   is 
intensified  on  dilution  with  water,  is  obtained. 

WEBER  (indican  in  urine). — Thirty  c.c.  of  the  urine 
are  boiled  with  an  equal  volume  of  hydrochloric 
acid  and  i  to  3  drops  of  dilute  nitric  acid.  In  the 
presence  of  indican,  the  liquid  becomes  opaque, 
and,  when  cooled  and  shaken  with  ether,  yields 
a  red  extract,  changing  to  violet,  whilst  a  blue 
froth  forms  on  the  surface  of  the  ether. 

WEBER-TOLLENS  (formaldehyde). — On  heating  a 
solution  of  formaldehyde  with  strong  hydro- 
chloric acid  and  phloroglucinol,  there  separates  a 
flocculent  precipitate,  which  is  first  white  and 
then  yellowish-red. 

WEIDEL  (xanthine) . — When  xanthine  is  evaporated 
with  chlorine  water  and  a  trace  of  nitric  acid,  it 
leaves  a  yellow  residue,  which,  when  treated  with 
gaseous  ammonia,  becomes  intense  yellowish- 
red. 

WEIGERT  (stain  for  bacteriology). — This  consists  of 
a  solution  of  2-4  grms.  of  methylene  blue, 
magenta,  or  victoria  blue  in  15  c.c.  of  alcohol, 
diluted  to  100  c.c.  with  water. 

WEIGERT-GRAHM  (stain  for  bacteriology)  .—Twenty- 
five  c.c.  of  a  saturated  alcholic  solution  of  methyl 
violet  or  gentian  violet  are  treated  with  i  c.c.  of 
aniline  and  4  to  5  c.c.  of  absolute  alcohol. 

WELLCOME  (morphine). — An  aqueous  solution  of 
calcium  chloride  (i  :  8)  gives  a  red  coloration 
with  morphine. 

WELMANN  (vegetable  oils). — One  c.c.  of  the  sample 
is  dissolved  in  5  c.c.  of  chloroform,  and  shaken 
for  a  minute  with  2  c.c.  of  an  aqueous  5  per  cent, 
solution  of  sodium  phosphomolybdate  acidified 
with  nitric  acid.  If  the  fat  contains  vegetable 
oils,  the  mixture  becomes  green,  the  colour 
changing  to  blue  on  the  addition  of  ammonia. 
Coconut  oil  and  rancid  oils  do  not  give  this 
reaction. 

188 


REAGENTS  AND   REACTIONS. 

WELMANN  (santonine). — Santonine  (o-i  grm.)  gives 
a  blood-red  coloration,  changing  to  violet  when 
treated  with  2  c.c.  of  strong  sulphuric  acid  and 
2  drops  of  ferric  chloride  solution. 

WENDER-NEUMANN  (dulcine). — On  treating  a  trace 
of  dulcine  with  a  few  drops  of  fuming  nitric  acid, 
an  energetic  reaction  takes  place,  yielding  a 
yellow  product,  which,  when  evaporated  to 
dryness,  leaves  a  yellow  residue  soluble  in  ether, 
alcohol,  and  chloroform.  When  this  residue  is 
treated  with  2  drops  of  phenol,  and  2  drops  of 
strong  sulphuric  acid,  it  gives  a  blood-red 
coloration,  which  does  not  alter  on  exposure  to 
the  air.  The  mass  is  soluble  in  chloroform, 
forming  a  red  solution,  the  colour  of  which  fades 
in  a  short  time. 

WENDER-NEUMANN  (dextrose). — The  reagent  con- 
sists of  a  solution  of  i  part  of  methylene  blue  in 
3,000  parts  of  water.  This  solution  is  decolorised 
when  rendered  alkaline  with  potassium  hyd- 
roxide, and  heated  with  dextrose. 

WENZELL  (alkaloids). — The  reagent  is  a  solution 
of  i  grm.  of  potassium  permanganate  in  200  grms. 
of  sulphuric  acid.  It  gives  various  colorations 
with  different  alkaloids. 

WEPPEN  (cevadine,  veratrine). — Sulphuric  acid  con- 
taining furfural  gives  a  yellow  coloration, 
changing  to  green  and  bright  blue,  with  solutions 
of  these  substances. 

WESELSKY  (phloroglucinol). — On  treating  a  solu- 
tion of  phloroglucinol  with  toluidine  nitrate  and 
potassium  nitrite,  a  coloration  is  produced,  which 
is  first  bright  yellow,  then  opalescent,  and 
finally  orange  and  red. 

WESELSKY  (olive  oil). — The  reagent  is  prepared  by 
saturating  nitric  acid  (sp.  gr.  1-25),  chilled  with 
ice,  with  the  vapours  developed  by  treating  starch 
with  nitric  acid.  It  is  used  for  the  elaidin  test 
(see  POUTET). 

189 


REAGENTS  AND  REACTIONS. 

WETZEL-KUNKEL  (carbon  monoxide  in  blood). — The 
blood  is  diluted  with  four  times  its  volume  of 
water,  and  treated  with  three  times  its  volume  of 
a  i  per  cent,  solution  of  tannin.  In  the  presence 
of  carbon  monoxide,  a  carmine-red  coloration  is 
produced,  whilst  normal  blood  gradually  turns 
grey. 

WEYL  (creatinine  in  urine). — Urine  containing 
creatinine  gives  a  ruby-red  coloration,  when 
treated  with  a  dilute  solution  of  sodium  nitro- 
prusside  and  with  sodium  hydroxide. 

WIESNER  (lignin). — (i)  A  dilute  aqueous  or 
alcoholic  solution  of  phloroglucinol,  followed  by 
strong  hydrochloric  acid,  imparts  a  cherry-red 
coloration  to  textile  fibres  containing  lignin. 
(2)  An  aqueous  solution  of  aniline  sulphate 
(i  per  cent.)  gives  a  yellow  coloration  with 
lignin. 

Wijs  (iodine  absorption). — Iodine  monochloride 
solution,  prepared  by  mixing  7*8  grms.  of  iodine 
trichloride,  and  8*5  grms.  of  iodine  per  litre.  . 

WITZ  (free  mineral  acids  in  vinegar  and  in  gastric 
juice). — A  solution  of  o-oi  grm.  of  methyl  violet 
in  100  c.c.  of  water  becomes  green  in  the  presence 
of  mineral  acids. 

WOLFF  (benzidine  and  toluidine) . — A  small  quantity 
of  the  substance  is  shaken  in  a  test-tube  with 
i  c.c.  of  glacial  acetic  acid  until  dissolved,  and 
the  solution  is  diluted  with  sufficient  water  to 
fill  three-fourths  of  the  tube,  and  is  then  treated 
with  a  few  drops  of  water  containing  lead  dioxide 
in  suspension.  In  the  presence  of  benzidine  or 
toluidine,  a  blue  coloration  is  produced,  which  is 
permanent  in  the  cold,  but  disappears  on  heating. 

WOLFF  (naphthols). — Naphthols  when  heated  to 
50°  C.  with  chloroform  and  alcoholic  potassium 
hydroxide  solution,  give  a  blue  coloration,  which 
changes  to  red  on  the  addition  of  hydrochloric 
acid. 

190 


REAGENTS  AND   REACTIONS. 

WORM-MULLER  (dextrose). — This  is  a  modification 
of  Fehling's  solution,  consisting  in  the  use  of 
different  proportions  of  the  constituents. 

WREVEN  (tassine). — A  few  drops  of  the  ethereal 
solution  of  the  alkaloid  are  allowed  to  evaporate 
on  a  porcelain  tile,  and  the  residue  is  treated 
with  i  or  2  drops  of  strong  sulphuric  acid.  The 
streaks,  which  are  thus  produced,  are  of  a  fine 
purple-red  colour  when  tassine  is  present. 

WRIGHT  (aconitine). — When  o-ooi  grm.  of  aconitine 
is  mixed  with  a  few  drops  of  a  solution  of  sugar 
of  medium  strength,  and  a  drop  of  strong  sul- 
phuric acid  is  added,  there  is  produced  at  the 
point  of  contact  of  the  liquid  a  red  zone,  which 
changes  rapidly  to  violet,  and  then  to  dirty 
blue. 

WURSTER  (nitrous  acid). — The  test  is  a  modification 
of  Griess's  reaction,  in  which  an  acid  solution  of 
ammonium  acetate  is  used  in  place  of  dilute 
sulphuric  acid. 

WURSTER  (tyrosine). — On  treating  a  boiling  aqueous 
solution  of  tyrosine  with  i  per  cent,  acetic  acid 
and  with  a  solution  of  sodium  nitrate,  a  red 
coloration  is  obtained. 


Y. 

YOUNG  (gallic  and  tannic  acids).— When  i  c.c.  of 
a  3  per  cent,  solution  of  potassium  cyanide  is 
added  to  i  c.c.  of  a  solution  of  gallic  acid,  it 
produces  a  ruby-red  colour,  which  disappears 
after  some  time,  but  reappears,  after  a  while,  on 
shaking  the  liquid.  Tannic  acid  and  pyrogallic 
acid  give  a  yellowish-red  colour  under  these 
conditions. 

YVON  (alkaloids). — Three  grms.  of  bismuth  sub- 
nitrate  are  boiled  with  40  c.c.  of  water,  and 
14  grms.  of  potassium  iodide  and  40  drops  of 
191 


REAGENTS  AND  REACTIONS. 

hydrochloric  acid  are  added.    This  reagent  gives 
colorations  or  red  precipitates  with  alkaloids. 
YVON  (urea). — See  HUFFNER. 


ZALESKI  (carbon  monoxide  in  blood}. — Two  c.c.  of 
the  blood  are  mixed  with  2  c.c.  of  water,  and 
treated  with  3  drops  of  a  saturated  solution  of 
copper  sulphate.  In  the  presence  of  carbon 
monoxide,  a  red  coloration  is  obtained,  whilst 
normal  blood  becomes  greenish-brown. 

ZEISEL  (colchicine}. — When  a  solution  of  2  mgrms. 
of  colchicine  in  5  c.c.  of  water  is  heated  for  two 
to  three  minutes,  over  a  small  flame,  with  5  to 
10  drops  of  hydrochloric  acid  and  4  to  6  drops  of 
a  10  per  cent,  solution  of  ferric  chloride,  it 
gradually  becomes  olive-green,  the  liquid  ulti- 
mately becoming  dark  green  and  turbid.  When 
this  liquid  is  shaken  with  chloroform,  a  ruby-red 
extract  separates,  whilst  the  supernatant  liquid 
is  olive- green. 

ZENKER  (fixative  solution  for  microscopy). — This 
consists  of  5  grms.  of  mercuric  chloride,  2-5  grms. 
of  potassium  bichromate,  and  i  grm.  of  sodium 
sulphate  in  100  c.c.  of  water.  A  few  drops  of 
acetic  acid  are  added  to  it  before  use. 

ZIEHL  (stain  for  bacteriology). — This  consists  of 
i  grm.  of  magenta,  10  grms.  of  absolute  alcohol, 
and  5  grms.  of  crystalline  phenol  in  100  c.c.  of 
water. 

ZULSER  (albumin). — A  strong  solution  of  chromic 
acid  gives  a  precipitate  with  liquids  containing 
albumin. 

ZWENGER  (cholesterol). — On  treating  a  crystal  of 
cholesterol  with  a  mixture  of  5  parts  of  sulphuric 
acid  and  I  part  of  water,  a  red  ring,  changing  to 
violet,  is  obtained. 


192 


TEST  PAPERS, 


TEST   PAPERS. 

TEST-PAPERS  are  of  considerable  use  in  volumetric 
analysis,  and  in  many  special  cases  of  clinical  or 
toxicological  research,  especially  those  involving 
reactions  in  which  gas  is  evolved,  or  readily 
volatile  substances  are  produced.  For  the  pre- 
paration of  test-papers,  filter-paper  of  the  best 
quality  is  used  ;  it  is  washed,  first  with  dilute  hydro- 
chloric acid,  then  with  very  dilute  ammonia  solu- 
tion, and  finally  with  water,  until  the  washings  are 
neutral. 

The  paper  thus  treated  is  immersed  in  a  solution 
of  the  indicator,  and  is  then  suspended  on  glass  rods 
to  dry  in  the  air,  in  a  place  protected  from  light  and 
free  from  dust.  As  soon  as  the  paper  is  perfectly 
dry,  it  is  cut  into  strips,  and  kept  in  well-closed 
bottles  of  coloured  glass.  Test-papers  may  be 
classified  into  three  groups  in  accordance  with  their 
use  :— 

1.  General  test  papers  for  acids  and  bases. 

2.  Test-papers  for  special  reactions. 

3.  Papers  for  clinical  tests. 


GENERAL  TEST-PAPER   FOR   ACIDS 
AND   BASES. 

ALKANINE  PAPER. — The  paper  is  impregnated 
with  a  3  per  cent,  alcoholic  solution  of  alkanine, 
or  with  the  ethereal  extract  of  the  alkanet  root. 
When  dry  it  is  pink.  In  the  presence  of  alkalies 
it  changes  to  green  or  blue,  whilst  acids  turn  it 
red  again. 

ALKANINE  (BLUE)  PAPER. — This  is  prepared  by 
dipping  the  red  paper,  made  as  described 
R.R.  193  13 


REAGENTS   AND   REACTIONS. 

above,  into  a  i  per  cent,  solution  of  sodium 
carbonate.  It  is  sensitive  to  a  hydrochloric  acid 
solution  of  i  :  80,000,  and  to  sulphuric  acid  of 
i  :  60,000. 

AZOLITMUS  PAPER. — The  paper  is  impregnated 
with  a  solution  of  i  part  of  azolitmus  and  i  part 
of  sodium  carbonate  in  a  litre  of  water,  with  the 
addition  of  just  sufficient  phosphoric  acid  to 
make  the  liquid  red.  It  gives  a  blue  coloration 
with  alkalies  and  a  red  coloration  with  acids. 

BRAZIL  WOOD  PAPER.—The  paper  is  immersed  in 
an  extract  of  Brazil  wood.  It  is  coloured 
carmine-red  by  alkalies,  and  decolorised  by  acids. 

CARMINE-RED  PAPER. — Paper  impregnated  with  an 
ammoniacal  solution  of  carmine-red  serves  as  an 
indicator  for  acids,  which  change  its  colour  to 
yellowish-red. 

COCHINEAL  PAPER. — The  paper  is  immersed  in 
cochineal  tincture.  It  is  coloured  yellowish-red 
by  acids,  and  violet  by  alkalies.  It  is  very 
sensitive. 

CONGO  RED  PAPER  (Herzberg). — The  paper  is 
impregnated  with  a  o-i  per  cent,  solution  of 
Congo  red  in  30  per  cent,  alcohol.  Its  colour  is 
changed  to  blue  by  acids,  whilst  alkalies  restore 
the  red  colour. 

DAHLIA  PAPER  (antocyanine,  georgina). — This  is 
prepared  by  immersing  the  paper  in  an  alcoholic 
extract  of  the  corollae  of  Georgina  purpurea. 
When  dry  it  is  of  a  bluish-violet  colour,  which 
is  changed  to  red  by  acids,  and  to  green  by 
alkalies. 

FLUORESCEIN  PAPER  (Zellner). — This  paper  is  pre- 
pared in  a  special  way.  The  basis  consists  of  a 
neutral  black  pigment,  and  upon  this  is  placed  a 
solution  of  fluorescein  made  into  an  emulsion 
with  an  alcoholic  solution  of  a  resin.  On  treating 
the  paper  with  alkali,  e.g.,  a  minute  trace  of 
ammonia,  it  produces  a  fine  >  green  fluorescent 
194 


TEST   PAPERS. 

reaction,   which  is  very  distinct  on   the   dark 
groundwork. 

H^MATOXYLIN  PAPER. — The  paper  is  washed,  first 
with  dilute  hydrochloric  acid,  and  then  with 
water,  and  is  immersed  in  a  solution  prepared 
by  digesting  10  parts  of  logwood  for  several  hours 
with  40  parts  of  alcohol  and  120  parts  of  water. 
The  liquid  is  heated  with  0-7  part  of  alum  (free 
from  iron)  and  7  parts  of  calcium  chloride,  dis- 
solved in  the  smallest  possible  amount  of  water 
acidified  with  hydrochloric  acid,  which  is  added 
drop  by  drop  until  a  red  coloration  sufficient  to 
tint  the  paper  is  obtained.  When  dry,  the  paper 
is  slightly  yellow  or  pink.  In  the  presence  of 
alkalies,  it  becomes  blue.  It  is  extremely  sen- 
sitive to  ammonia. 

LACMOID  (OR  RESORCINOL  BLUE)  PAPER. — Lac- 
moid  is  prepared  by  heating  resorcinol  with 
sodium  nitrite  at  a  moderate  temperature.  It 
is  soluble  in  alcohol  (0-2  grm.  in  100  c.c.),  and 
the  alcoholic  solution  is  used  for  impregnating  the 
paper.  It  is  coloured  red  by  acids,  and  blue  by 
bases.  It  is  a  good  reagent  for  strong  acids  and 
bases,  and  for  ammonia,  but  is  not  suitable  for 
weak  acids  and  for  nitrous  acid. 

LITMUS  PAPER. — 100  grms.  of  litmus  are  powdered, 
and  extracted,  first  for  half  an  hour  with  500  grms. 
of  hot  95  per  cent,  alcohol,  and  then  with  two 
successive  portions  of  250  grms.  of  the  hot  alco- 
hol, for  thirty  minutes  each  time.  The  residue  is 
digested  for  twenty-four  hours  with  i  litre  of 
distilled  water.  The  extract  is  filtered  through 
cotton-wool,  and  the  filtrate  is  divided  into  two 
parts.  One  of  these  is  treated  with  dilute 
phosphoric  acid  until  it  becomes  red.  The 
second  portion  is  then  treated  with  the  same  acid, 
and  added  to  the  first,  and  the  whole  is  allowed 
to  stand.  It  is  filtered  from  the  deposit,  and  used 
for  the  impregnation  of  filter-paper.  Litmus 
195  13-2 


REAGENTS   AND   REACTIONS. 

paper  turns  red  with  acids,  and  blue  with 
alkalies. 

MAGENTA  PAPER. — The  paper  is  immersed  in  a 
solution  of  magenta,  to  which  has  been  added 
sulphuric  acid  until  a  yellowish-brown  coloration 
is  obtained.  When  dry,  the  paper  is  yellow,  and 
extremely  sensitive  to  ammonia,  which  changes 
its  colour  to  carmine-red. 

MARSHMALLOW  PAPER  (Stevenin). — The  paper  is 
immersed  in  an  extract  prepared  by  macerating 
20  parts  of  the  flowers  of  Altea  rosea  with  a  mix- 
ture of  100  parts  of  water,  900  parts  of  alcohol, 
and  i  part  of  ammonia  solution.  The  paper 
becomes  bluish-green  on  contact  with  alkali, 
whilst  acid  turns  it  red. 

METHYL  ORANGE  OR  (HELIANTHIN)  PAPER. — The 
paper  is  impregnated  with  an  aqueous  solution 
of  methyl  orange,  obtained  by  dissolving  0-02 
grm.  of  the  dyes  tuff  in  100  c.c.  of  boiling  water, 
and  filtering  the  liquid.  The  paper  becomes 
orange-red  with  acids,  and  yellow  with  bases. 
It  is  particularly  suitable  for  strong  acids,  and 
for  phosphoric  and  sulphurous  acids.  Weak 
mineral  and  organic  acids  do  not  react  with  it. 
Strong  bases,  and  notably  amino-organic  bases, 
give  a  good  reaction. 

METHYL  VIOLET  PAPER. — The  paper  is  impregnated 
with  an  aqueous  solution  of  methyl  violet 
(i  :  200).  When  dry,  the  paper  is  violet.  It  is 
changed  to  green  or  yellowish-green  by  strong 
acids,  whilst  bases  restore  the  violet  colour. 
Acetic  acid  does  not  affect  this  test-paper. 

PHENOLPHTHALEIN  PAPER. — The  paper  is  immersed 
in  a  i  per  cent,  solution  of  phenolphthalein  in 
96  per  cent,  alcohol.  It  becomes  red  with  alkalies, 
and  is  decolorised  again  by  acids.  It  is  par- 
ticularly suitable  for  strong  acids  and  bases,  but 
cannot  be  used  with  ammonia. 

ROSOLIC  ACID  PAPER. — The  paper  is  impregnated 
196 


TEST   PAPERS. 

with  a  neutral  0-2  per  cent,  alcoholic  solution  of 
rosolic  acid.  In  the  presence  of  strong  acids  or  of 
carbonic  acid  the  paper  becomes  yellow,  whilst 
alkalies,  baryta  water,  and  alkali  carbonates  turn 
it  red.  The  presence  of  ammonium  salts  modifies 
the  reaction,  and  affects  the  sensitiveness  of  the 
paper. 

TROP^OLIN  PAPER  (Boas-Lucke). — The  paper  is 
immersed  in  a  o-i  per  cent,  alcoholic  solution  of 
tropaeolin  OO.  It  gives  a  red  coloration  with 
acids,  and  a  yellow  coloration  with  alkalies.  It 
is  suitable  for  oxalic  acid  and  other  organic  acids, 
and  is  not  affected  by  carbonic  acid. 

TURMERIC  PAPER. — This  is  prepared  by  impreg- 
nating the  paper  with  an  alcoholic  solution  of 
turmeric.  It  is  an  indicator  for  caustic  alkalies, 
which  turn  it  reddish-brown.  It  gives  a  rose- 
brown  coloration  with  boric  acid. 

TURMERIC  (CURCUMINE)  PAPER. — This  behaves  in 
the  same  way  as  the  preceding  paper.  It  is 
prepared  by  immersing  the  paper  in  an  alcoholic 
solution  of  curcumine.  It  is  particularly  suitable 
for  the  detection  of  minute  quantities  of  boric 
acid. 


PAPERS   FOR   SPECIAL  TESTS. 

COPPER  SULPHATE  AND  GUAIACUM  TINCTURE 
PAPER. — The  paper  is  impregnated  with  a 
i  per  cent,  alcoholic  solution  of  guaiacum  resin 
and  dried,  and  is  then  dipped  in  a  solution  of 
copper  sulphate  (i  :  2,000).  In  the  presence  of 
hydrocyanic  acid  it  turns  blue  (Schonbein  and 
Pagenstecker). 

GOLD  CHLORIDE  PAPER  (ozone). — A  paper  impreg- 
nated with  gold  chloride  becomes  violet  in  the 
presence  of  ozone  (Bottger). 

INDIGO  PAPER  (oxygen). — The  paper  is  impreg- 
197 


REAGENTS  AND   REACTIONS. 

nated  with  a  solution  of  indigo.    It  is  used  for  the 
detection  of  oxygen. 

LEAD  ACETATE  PAPER  (hydrogen  sulphide). — The 
paper  is  immersed  in  a  10  per  cent,  solution  of 
lead  acetate.  It  is  darkened  on  contact  with 
hydrogen  sulphide. 

METAPHENYLENEDIAMINE  PAPER  (Griess's  yellow 
paper). — The  paper  is  impregnated  with  an 
alcoholic  solution  of  metaphenylenediamine.  It 
is  coloured  yellow  or  brown  by  nitrous  acid  or 
nitrites. 

NAPTHYLAMINE  PAPER  (Griess's  red  paper). — The 
paper  is  immersed  in  an  alcoholic  solution  of 
sulphanilic  acid  and  of  a-naphthylamine  hydro- 
chloride.  It  becomes  pink  on  contact  with 
nitrous  acid  or  nitrates. 

PALLADIUM  CHLORIDE  PAPER  (reducing  substances). 

-This  is   a  paper  saturated  with   a  solution 

(i  :  12)    of   palladous    sodium    chloride.      It   is 

turned  black  by  reducing  substances,  such  as 

carbon  monoxide. 

SCHIFF'S  PAPER  (dextrose  and  carbohydrates). — The 
paper  is  impregnated  with  a  mixture  in  equal 
volumes  of  glacial  acetic  acid  and  xylene,  with 
the  smallest  possible  amount  of  alcohol.  The 
substance  under  examination  is  first  heated 
with  sulphuric  acid,  and,  if  it  contains  dextrose 
or  other  carbohydrates,  it  will  then  give  a  red 
coloration  to  the  paper. 

SILVER  PAPER  (Schiff)—Tlds  is  used  for  the 
detection  of  arsenic  (yellow  coloration),  phos- 
phorus (black),  and  uric  acid  (brown  coloration). 

STARCH  IODIDE  PAPER  (oxidising  substances). — One 
part  of  starch  is  boiled  with  100  parts  of  water 
and  filtered,  and  5  parts  of  potassium  iodide  are 
dissolved  in  the  filtrate.  Paper  impregnated 
with  this  solution  becomes  blue  when  applied  to 
oxidising  substances,  such  as  chlorine,  chloric 
acid,  iodic  acid,  bromic  acid,  and  ozone. 
198 


TEST  PAPERS. 

TETRAMETH YL-^>-PHEN YLENEDIAMINE  PAPER  (ozone, 
hydrogen  peroxide,  nascent  oxygen). — Paper  im- 
pregnated with  this  substance  gives  an  intense 
violet-blue  coloration  on  contact  with  ozone, 
hydrogen  peroxide,  or  nascent  oxygen  in  neutral 
or  acetic  acid  solution.  When  the  paper  thus 
coloured  is  boiled  with  alcohol,  it  is  decolorised 
(Wurster). 

THALLIUM  PAPER  (ozone). — The  paper  is  saturated 
with  a  10  per  cent,  solution  of  thallium  hydroxide 
obtained  by  treating  a  solution  of  thallium 
sulphate  with  baryta  water.  It  becomes  brown 
on  contact  with  ozone. 

PAPERS  FOR  CLINICAL  TESTS. 

ACIDS  IN  GASTRIC  JUICE  (Boas-Lucke). — This  is 
tropaeolin  paper.  It  becomes  red  when  treated 
with  free  hydrochloric  or  lactic  acids. 

ALBUMIN  (GEISSLER). — (i)  Potassium  Mercury 
Iodide  and  Citric  Acid  Papers. — The  paper  is 
saturated  with  a  strong  solution  of  citric  acid, 
whilst  other  strips  are  immersed  in  a  solution 
containing  3  per  cent,  of  mercuric  chloride  and 
15  per  cent,  of  potassium  iodide.  For  the  detec- 
tion of  albumin  in  urine,  the  sample  is  first 
treated  with  the  citric  acid  paper  and  then  with 
the  iodide  paper.  In  the  presence  of  albumin,  a 
precipitate  is  formed. 

(2)  Citric  and  Picric  Acid  Paper  (Olliver). — 
The  paper  is  impregnated  with  a  2  per  cent, 
solution  of  these  acids.    When  it  is  introduced 
into  urine  containing  albumin  a  precipitate  is 
formed. 

(3)  Sodium  Tungstate  and  Citric  Acid  Paper 
(Olliver). — The  paper  is  immersed  in  a  concen- 
trated   solution    of    these    substances.     When 
introduced  into   albuminous   urine,  it  yields  a 
precipitate.     A  precipitate  is  also  formed  in  the 

199 


REAGENTS  AND   REACTIONS. 

presence  of  mucine,  creatinine,  peptones,  and 
uric  acid. 

(4)  Potassium  Mercuric  Iodide  Paper   (Hoff- 
mann).— The    paper    is    impregnated    with    a 
mixture  composed  of  a  50  per  cent,  solution  of 
potassium  iodide  and  of  a  5  per  cent,  solution  of 
mercuric  chloride.     On  introducing  strips  of  this 
paper  into  albuminous  urine,  previously  acidified 
with  acetic  acid,  a  precipitate  is  obtained. 

(5)  Potassium  Ferrocyanide   and  Citric  Acid 
Papers. — Two    papers    are    used,    impregnated 
respectively  with  potassium   ferrocyanide   and 
with  citric  acid.     Introduced  into  albuminous 
urine  they  produce  a  precipitate. 

PHLOROGLUCINOL- VANILLIN  PAPER  (Gunzburg).— 
This  may  be  used  for  the  detection  of  lignin  in 
paper,  and  also  of  free  hydrochloric  acid  in  gastric 
juice.  It  is  prepared  by  saturating  filter  paper 
with  a  solution  of  i  part  of  phloroglucinol  and 
2  parts  of  vanillin  in  30  parts  of  alcohol.  It  is 
coloured  red  by  hydrochloric  acid,  or  by  lignin. 

SUGAR  IN  URINE  (Olliver). — Two  papers  are  used, 
impregnated  respectively  with  a  solution  of 
indigo-carmine  and  of  sodium  carbonate.  In 
the  presence  of  dextrose,  these  papers,  when 
introduced  into  the  urine,  give  successively  a 
reddish-green  and  yellow  colorations. 


200 


COLLECTIVE  INDEX. 


COLLECTIVE  INDEX  OF  REAGENTS 
AND  REACTIONS  OF  DIF- 
FERENT SUBSTANCES. 

A. 

Abrastol.  —  Brand  —  Sangle,  Ferriere  —  Sanna, 
Pintus. 

A  cetaldehyde-. — Simon. 

A  cetanilide. — Rittsert. 

Acetone.  --  Chautard  --  Denniges  —  Ehrlich  — 
Ellram  —  Gunning  —  Legal  —  Le  Noble  —  Lie- 
ben  -  -  Malerba  -  -  Messinger  —  Pentzold  — 
Reynold — Rimini — Vitali. 

A  ceto-acetic  A  cid.  —  Arnold  —  Deniges  —  Gerhardt 
— Oudreyovich — Riegler. 

A  conitine. — Herbst — Wright. 

Adrenaline.  —  Aller,  Frankel  —  Ewins  —  Gunn  — 
Harrison — Kurt-Boas. 

Albumin.   -  -  Almen  -  -  Alpers  —  Bodecker  - 
Carrez  --  Christensen  --  Cohen  —  Esbach  — 
Fiirbringer  —  Galippe  —  Gauthier  —  Gouver  - 
Guerin  -  -  Hammarsten  —  Heller  —  Hilger  — 
Jaworowsky  —  Jolles  —  Lugol  —  Mac  William  — 
Mankiewicz  --  Mehu  --  Panum  —  Pollacci  - 
Possner  —  Raabe  —  Riegler  —  Rose  —  Rosen- 
bach  —  Spiegler  —  Strzyzowscky  —  Tanret  — 
Zulser. 

Alcohol.  —  Drescher  —  Grassini  —  Jacquemart  — 
Merch. 

Aldehydes.  —  Bela  —  Crismer  —  Gayon  —  Nessler 
—  Schiff  —  Simon. 

Alkali  (Caustic). — Dobbin. 

Alkaloids. — Arnold  —  Bertrand  —  Bouchardat  - 
Brouardel  —  Brunner  —  Buckingham  —  Caro  — 

201 


REAGENTS  AND   REACTIONS. 

Czumpelitz  —  Davy  —  Delf  —  Delf ,  Schwarzen- 
bach  —  Dittmar  —  Dragendorff  —  Erdmann  - 
Fraude  -  -  Frohde  -  -  Godefroy  -  -  Godrefroy, 
Laubenheimer  —  Guareschi  —  Hager  —  Jawo- 
rowsky  -  -  Johannson  -  -  Jorissen  --  Kraut  - 
Lafon,    Keller  —  Langley  —  Lepage  —  Luchini 
— Mandelin  —  Mangini  —  Marine  —  Marquis  - 
Mayer  —  Mecke  —  Melzer  —  Orlows,  Horst  - 
Pesci  —  Planta  —  Scheibler  —  Schlagdenhaufen 

-  Schneider  -  -  Schultze  -  -  Sonnenschein  - 
Valser  —  Vitali  —  Wagner  —  Wenzell  —  Yvon. 

Almond  Oil.  —  Bieber  —  Maben  —  Nickles. 

Aloes.  —  Apery  —  Borntrager  —  Cripp,    Dymont 
— Dieterich  —  Hirschsohn  —  Klunge. 

A  loine. — Dieterich. 

Aluminium  (Salts  of). — Goppelsroder. 

Ammonia.  —  Curtmann  —  Donath  —  Nessler. 

A  nilides. — Deniges. 

Aniline.  —  Beissenhirtz  —  Duflos  —  Hoffmann  — 
Jacquenin  —  Letheby  —  Runge  —  Vitali. 

Antipyrine.  —  Bougault  —  Carrez  —  Knorr. 

Apiol. — Jorissen. 

Apomorphine. — Grimbert — Schmidt. 

Arachis  Oil. — Renard. 

Arbutine. — Dahnon. 

Arsenic.  -  -  Bettendorf  —  Deniges  -  -  Gosio  — 
Gutzeit  —  Marsh  —  Reinsch  —  Schlickum. 

A  spidospermine. — Czerniewski. 

A  tr  opine. — Gerrard. 

B. 

Bacteriology  (Stains  for).  —  Allen  —  Cohn  - 
Czaplewski  -  -  Ehrlich  -  -  Ehrlich,  Biondi  - 
Flemming  —  Gabbet  --  Gibbs  —  Giemsa  - 
Grahm  -  -  Giinther  -  -  Hamilton  -  -  Koch  - 
Kiihne  —  Loffler  —  Nicolle,  Moran  —  Pick  - 
Roux  —  Weigert  —  Weigert,  Grahm  —  Ziehl. 

Balsams  and  Resin. — Hirschsohn. 
202 


COLLECTIVE  INDEX. 

Benzanilide. — Mussi. 

Benzidine. — Wolff. 

Benzene  and  Petroleum  Spirit. — Gawalowsky. 

Benzoic  Acid. — Bodde — Jorissen. 

Berberine. — Klunge. 

Biliary      Acids.   -  -  Bischoff  -  -   Dragendorff  — 

Drechsel  —  Kulz  —  Mylius  —  Neebauer  —  Pet- 

tenkofer  —  Udransky  —  Vitali. 
Biliary  Pigments.  —  Biffi  —  Capranica  —  Cunisset 

-  Dragendorff  —  Drechsel  —  Fleischl  —  Frohde 
— Gerhard!  -  -  Gluzinsky  —  Gmelin  —  Ham- 
marsten  —  Hilger  —  Hoppe   Seyler  —  Huppert 

—  Jaksch  —  Jolles  —  Kathrein  —  Le  Noble  — 
Marechal  —  Paul  -  -  Rosenbach  -  -  Rosin  — 
Schlesinger  —  Smith  —  Stokwis  —  Ultzmann. 

Bilimbin. — Ehrlich. 

Bismuth  (Salts  of). — Schneider. 

Bitter-Almond  Water. — Daclin. 

Blood — Almen  —  Baecchi  —  Bremer  —  Deen  (van) 

-  Donogany  -  -  Falk  —  Gannther  -  -  Heller — 
Hiihnenfeld  —  Lechini  —  Schaer  —  Schlesinger, 
Hoist  -  -  Selmi  —  Sonnenschein  -  -  Struve  — 
Teichmann  —  Ultz. 

Bromine. — Deniges — Guareschi — Jolles. 


C. 

Caffeine. — Archetti  —  Armani,    Barboni  —  Roch- 

leder — Stenhouse. 
Camphor. — Dumont. 
Cantharidine. — Eboli. 
Carbon       monoxide. — Fodor        •    Habermann    — 

Hoppe  Seyler  —  Ipsen  —  Katayama  —  Rubner 
-  Salkowski  —  Schulz  —  Wenzel,    Kunkel  — 

Zaleski. 

Castor  Oil. — De  Vetere — Draper — Ferraro. 
Cellulose.  --  Cutolo   -  -  Molisch   -  -   Schultze    - 

Schweitzer. 

203 


REAGENTS  AND   REACTIONS. 

Cerium  (Salts  of). — Plugge. 

Cevadine. — Weppen. 

Chloral. — Jaworowsky  —  Ogston  —  Renter. 

Chlorates. — Deniges. 

Chloroform. — Dupony  —  Hoffmann  —  Neebauer  — 

Schwarz — Vitali. 

Chromic  A  cid. — Donath — Caro — Fischer. 
Chrysarobine. — Leger. 
Chrysophanic  Acid. — Leger. 
Cholesterol. — Hager  -  -  Kreis  —  Liebermann  - 

Obermuller  —  Salkowski  —  Schiff  —  Udransky 

— Zwenger. 

Cinnamic  Acid. — Jorissen. 
Cisteine. — Andre  asch. 
Cistine. — Baumann,       Goldmann    —    Liebig    — 

Miiller. 
Citric     Acid. — Chapman,     Smith  -  -  Deniges  — 

Haussler  —  Mann  —  Pusch  —  Sabanin,    Las- 

kowsky — Stahre. 
Cobalt    (Salts    of). — Caro,    Fischer  —  Donath  — 

Fischer  —  Pagel  —  Rusting  —  Skey  —  Tatter- 
sail — Thenard — Vogel. 
Cocaine. — Biel     —     Fliickiger     —    Geitherr    — 

Giesel  —  Kuborne  —  Metzger  —  Schaffer  - 

Scharge — Silva  (Ferreira  da) — Szankay. 
Cochineal. — Lagorche. 
Codeine. — Faby  —   Lafon   —   Pellagri   —   Raby 

Tattersall. 

Colchicine. — Kippenberger — Zeisel. 
Colza  Oil. — Schneider. 
Coniine. — Melzer — Selmi. 
Copaiba    balsam. — Dodge,  Holscott  —  Ellram  - 

Fliickiger  —  Hirschsohn. 
Copper  (Salts  of). — Aliamet  —  Bach  —  Deniges  — 

Jaworowsky — Pagenstecker. 
Coriander  Seed. — Uffelmann. 
Cotton  Oil. — Bechi  —  Conroy  —  Deiss,  Gannther  — 

Halphen  —  Hirschsohn  —  Labiche  —  Milliau. 
Creatinine. — Jaffe  —  Kerner  —  Weyll. 
204 


COLLECTIVE  INDEX. 

Creosote. — Brandes. 

Cresol. — Arnold,  Werner — Udransky. 

D. 

Dextrose. — Agostini  —  Allen  —  Almen  —  Baeyer  — 
Barfold  -  -  Bottger  -  -  Braun  —  Bremer  - 
Briicke  --  Campani  --  Crismer  --  Criswell  - 
Degener  —  Drechsel  -  -  Dudley  —  Duyk  - 
Einhorn    -    •   Fehling   -   -   Gaud    -   -   Gause    - 
Gentele  —  Gerrard  —  Hager,    Gawalowsky  - 
Haines   —  Hoppe  Seyler  --  Ihl  --  Jaksch  - 
Jaworowsky  —  Johnson  —  Lehmann  —  Leismer 

—  Lowe  —  Lowenthal  —  Maumene  —  Moore  — 
Mulder  —  Nylander  —  Ost  —  Pavy  —  Pelouze  — 
Pentzold  —  Polliti  —  Rosenbach  —  Rubner  - 
Schiff   •    -    Schmidt  —  Soldaini  —  Tollens  — 
Trommer. 

Diazo  Reaction. — Ehrlich. 

Digitaleine. — Grandeau — Kiliani. 

Digitalis. — Brissemoret,  Derrien. 

Digitaline. — Grandeau — Lafon. 

Digitonine. — Keller. 

Digitoxine. — Kiliani. 

Dulcine. — Berlinerblau  —  Jorissen  —  Morpurgo  — 

Ruggeri  —  Thomas — Wender. 
Dyestuffs  (Coal-tar}. — Arata  —  Blarez  --  Bottger 

—  Cazeneuve  —  Cottini,  Fantogini  —  Debrun  — 
Faure  —  Girard. 

E. 

Ergot  of  Rye. — Hoffmann. 
Ergotine. — Keller. 

Erithrosderotine. — Dragendorff,  Podwyssotzki. 
Eserine. — Silva  (Ferreira  da). 
Essences  (Aromatic] . — Arznberger — Fabris. 
Essential  Oils. — Duyk — Fabris. 
205 


REAGENTS  AND   REACTIONS. 

Ether. — Jorissen. 

Ethyl  Sulphide. — Liebermann. 

Eugenol. — Chapman. 

F. 

Fats. — See  Oils. 

Fatty  Acids. — Jacobsen. 

Flesh. — Brautigam,  Edelmann — Eber. 

Flour. — Hoffmann — Uffelmann. 

Fibres        (Textile) . — Bottger  Jacquemin 

Overbech     —    Peligot    —    Schlossberger 

Schweitzer. 

Formaldehyde. — Goldschmidt  —  Hehner  —  Jorissen 
-  Judd  —  Kentmann  —  Leblin  —  Mitchell  - 

Neuberg  —  Pilhastry  —  Pollacci  —  Riegler  - 

Rimini  —  Schryver  —  Therenon  —  Todtenhaupt 

— Trillat — Weber,  Tollens. 
Fruit  Acids. — Mitchell. 
Fusel  Oil. — Jorissen. 

G. 

Gallic  A  cid. — David — Dudley — Young. 

Gastric  Juice. — Arnold — Boas — Cohn,    Mehring  - 
Contejean  —  Ewald  —  Giinzburg  —  Jager  (de)— 
Jaksch  —  Mohr  —  Rabuteau  —  Schuchardt  - 
Topfer  —  Uffelmann  —  Velden    (van    der)  - 
Vournasos — Witz. 

Glycerin. — Bottger — Griinhat — Kohn  --  Reich  - 
Senier — Lowe. 

Glycogen. — Best — Knapp. 

Guaiacol. — Jaworowsky. 

Gum  Ammoniacum. — Plugge. 

Guanine. — Capranica. 

H. 

Hcematin. — Podwyssotzki. 
Hemoglobin. — Ladendorf. 
206 


COLLECTIVE   INDEX. 

Hexoses. — Rasmussen. 

Hipp  uric  A  cid .  — Lii  eke . 

Hydrochloric   Acid.  —  Boas  —  Cohn,    Mehring  — 

Contejean  —  Cordier  —  Ewald  —  Giinzburg  — 

Jaksch — Mohr — Rabuteau. 
Hydrocyanic     Acid.  —  Carey-Lea  -  -  Frohde  - 

Hlasiwez  —  Husemann  —  Ittner  —  Robert  — 

Lassaigne  —  Liebig  —  Pertusi,     Gastaldi  - 

Preyer  —  Schonbein  —  Vortmann. 
Hydrogen  Peroxide.  —  Bach  —  Barralet  —  Bottger 
-  Deniges  —  Ilosvay  —  Schonbein  —  Vanino 

Seemann. 
Hydrogen  Sulphide.  —  Caro,  Fischer  —  Curtmann 

—  Fischer  —  Ganassini  —  Krai  —  Lauth. 
Hydroxylamine. — Angeli. 
Hypoxanthine. — Kossel. 

I. 

Indican.  —  Ehrlich  -  -  Hammarsten,  Jaffe  — 
Klett  —  Loubiou  —  MacMunn  —  Obermayer  — 
Weber. 

Indol  —  Baeyer  —  Kitasato,  Salkowski  —  Legal  — 
Nencki. 

Inosite. — Gallois — Scherer — Seidel. 

Iodine. — Alf  raise — Sadlund. 

Iodine  Absorption. — Hanus  —  Hubl  (von)  —  Wijs. 

lodoform. — Lustgarten — Vitali. 

Iron  (Salts  of). — Deniges. 

Isoeugenol. — Chapman. 

Isosafrol. — Chapman. 

L. 

Lactic    Acid.  —  Arnold  —  Boas  —  Uffelmann  - 

Vournasos. 
Lactose. — Rubner. 
Lcevulose. — Seliwanoff. 
L  ecithin .  — Orlow. 

20,7 


REAGENTS  AND   REACTIONS. 

Leucine. — Hoffmeister. 

Lignin.  —  Dahlmann  —  Hegler  —  Hohnel  (von)  - 
Piutti  —  Wiesner. 

M. 

Malic  Acid. — Hilger. 

Manganese  (Salts  of). — Crum — Deniges. 

Melanin. — Eiselt — Jaksch — Thormahlen. 

Melanogen. — Jaksch. 

Mercaptans. — Deniges. 

Mercury. — G  aglio — Jolles . 

Methtem  oglobin .  — Kob  ert . 

Methyl  Alcohol.  —  Deniges,   Mulliken,  Scudder. 

Microscopy    (Stains  for).  —  Bohmer  —  Croker  - 

Czokor  —  Delafield  —  Dural  —  Ehrlich  —  Erliki 
-  Fol  —  Frey  —  Gibbe  —  Giemsa  —  Golgi  - 

Grenadier  —  Hanstein  —  Kleinenberg  —  Nicolle 

—  Pacini  —  Pappenheim  —  Rable  —  Sahli  — 

Schlutze  —  Zenker. 
Milk.  —  Dupony  —  Ostertag,   Arnold  —  Schaffer 

— Storch. 
Mineral  Acids.  —  Egger  —  Hager  —  Hiiber  - 

Jager  —  Payen  —  Witz. 
Mineral  Oils.  —  Demski,  Morawski. 
Morphine.  —  Bruylants  —  Chastaing,   Barrilot  - 

Fliickiger  —  Husemann  —  Jorissen  —  Kerner  — 

Robert  —  Lamal  —  Otto  —  Pellagri  —  Robinet 

Schaer  —  Tattersall  —  Wellcome. 
Mustard  Oil. — Colasanti. 

N. 

Naphthalene. — Pentzold. 

Naphthols.  —  Aymonier  —  Leger  —  Richardson  - 

Wolff. 

Narceine. — Arnold — Vogel. 

Narcotine.  —  Cuerbe  —  Dragendorff  —  Wangerin. 
Nataloine. — Histed. 

208 


COLLECTIVE   INDEX. 

Nickel  (Salts  of).  —  Grossmann  —  Tschugaeff. 

Nicotine.  —  Roussin  —  Schindelmeister  —  Selmi. 

Nitric  Acid. — Alessandri,  Ganassini  —  Boussin- 
gault  —  Braun  —  Curtmann  —  Deniges  —  Dess- 
bassin  —  Hoffmann  —  Horsley  —  Ince  - —  Lindo 

-  Longi  —  Pollack  —  Reichardt  —  Sprengel. 
Nitrous  Acid. — Alessandri,  Ganassini  —  Armani, 

Barboni  —  Bottger  —  Buywid  —  Curtmann  - 
Deniges  —  Erdmann  —  Frankland  —  Grandval, 
Layoux  —  Griess  —  Ilosvay  — •  Jorissen  —  Lindo 

-  Lunge  —  Manseau  —  Riegler  —  Schaffer  — • 
S chaffer,  Schuyten — Trommsdorff — -Wiirster. 


O. 

Oils  and  Fats  :  Olive  Oil. — Barbot  -  -  Basch  — 
Baudouin  -  -  Bechi  —  Behrens  —  Bellier  — 
Bieber  —  Bishop  —  Boudet  —  Brulle  —  Cailletet 

-  Camoin  —  Conroy  —  Crace   Calvert  —  Deiss 

-  De  Vetere  —  Ferraro  —  Gassend  —  Halphen 
— Hauchecorne  -  -  Heydenreich  -  -  Labiche  — 
Lewin  —  Milliau  — •  Penot  —  Poutet  —  Renard 

—  Schneider  —  Soltsien  —  Storch,  Morawski  — 
Tambon  —  Tocher  —  Tortelli,  Ruggeri  —  Villa- 
vecchia,  Fabris  —  Wellmann  —  Weselsky. 

Oxydases. — Meyer — Schmidt. 

Ozone. — Erlwein,  Weyl — Manchot,  Kampeschultz 
— Schonbein. 

P. 

Papaverine. — Tattersall. 

Peach  Oil.—  Nickles. 

Pentosans .  — S  alko  wski . 

Pentoses. — Bial — Tollens. 

Peptones.  —  Devoto  —  Gorup,  Besanez  —  Possner 

— S  alko  wski. 
Persulphates. — Caro. 
Phenacetin . — Crinon — Ri  tsert . 

R.R.  209  14 


REAGENTS  AND   REACTIONS. 

Phenol.  —  Arnold,  Werner  —  Berthelot  —  Bodde 
-  Cotton  —  Davy  —  Desesquelle  —  Eykmann 
—  Guareschi  —  Hoffmann  —  Hoppe  Seyler  - 

Jacquemin  —  Landolt  —  Lex  —  Melzer  —  Pent- 

zold,    Fischer  —  Pollacci  —  Salkowski  —  Tom- 

masi  —  Udranszky. 
Phenols.  —  Allen  —  Endemann  —  Fresenius  - 

Lambert  —  Liebermann  —  Millon  —  Plugge. 
Phloridzine. — Nickel. 
Phloroglucinol. — Weselsky. 
Phosphorus. — Dusart,  Blondot — Scherer. 
Picric  Acid. — Christel — Swoboda. 
Picrotoxine. — Melzer  --  Minowic  --  Oglialoro  - 

Otto. 

Pilocarpine. — Lenz. 
Potassium  (Salts  of). — Carnot. 
Proteins.  —  Adamkiewicz  —  Axenfeld  —  Berzelius 

—  Briicke  —  Krasser  —  Liebermann  —  Mulder 
— Petri  —  Piotrowski  —  Raffaele  —  Raspail  - 
Reichl  —  Schultze. 

Ptomaines. — Brouardel,  Boutmy. 
Pus. — Day. 
Pyramidon. — Jolles. 
Pyridine. — Anderson. 
Pyrocatechol. — Ebstein,  Miiller. 

Q- 

Quinidine. — Brand — Hirschsohn. 

Quinine. — Brand  —  De  Vry  —  Eibart  —  Fliickiger 

—  Grahe  —  Herapath  —  Hirschsohn  —  Jawo- 
rowsky  —  Kerner  —  Pollacci. 

Quinoline .  — Anderson . 
Quinuric  Acid. — Jaffe. 

R. 

Resins. — Don  at  h. 

Resin     Oil. — Cornette  —  Demski,     Morawski  - 
Storch,  Morawski. 

210 


COLLECTIVE   INDEX. 

Resorcinol. — Bodde — Ferraro — Torti. 
Rhubarb. — Prosch. 

S. 

Saccharin. — Bornstein  —  Kastle  —  Leys  —  Lindo 
-  Pinette,     Schmidt  —  Possetto,     Issoglio  — • 

Schmidt  —  Tortelli,  Piazza  —  Vitali,  Muhler  — 

Wauthers. 
Safrol. — Chapman. 
Saffron. — Kraemer. 
Salicylic  Acid. — Bodde  —  Cenci  —  Van   Itallie  — 

Jorissen  —  Schultz. 
Salop  hen. — Goldmann. 
Salvarsan. — Abelin. 
Santonine. — Crouzel    —    Daclin    —    Ferraro    — 

Jaworowsky    —    Neuhaus  Reichard 

Theater — Wellmann. 
Scatol. — Amand    —    Ciamician,       Magnanini    — ' 

Udranszky. 
Sesame     Oil. — Basch  —  Baudouin  —  Bellier  — 

Bishop   —   Bremer  -  -   Camoin   —   Fliickiger, 

Behrens  —  Gassend  —  Lewin  —  Soltsien  — 

Tambon  —  Focher  —  Villavecchia,  Fabris. 
Silk. — Hermann — Lowe — Truchot. 
Solanine. — Bauer — Claras — Stroppa. 
Sparteine. — Marque. 
Sperm  (Stains) . — Florence. 
Strychnine. — Allen — Malaquin — Otto — Tafel. 
Sucrol. — See  Dulcine. 
Sugars. — Bottger  —  Conrady  —  Fischer  —  Hager 

— Ihl  —  Mathieu,  Plessy  —  Molisch  —  Neubauer 

Vogel — Reich — Riegler. 
Sulphonal. — Rittsert — Schwarz — Vitali — Vulpius. 


T. 

Tannic  Acid. — Gardiner — Young. 
Tannin. — Baeme — Carpene— David. 

211  14—2 


REAGENTS  AND   REACTIONS. 

Tartaric  Acid. — Cailletet  —  Campbell,  Starch  - 
Chapman,  Smith  -  -  Crismer  -  -  Deniges  - 
Fen  ton  —  Ganassini  —  Mohler  —  Pusch. 

Tassine. — Wreven. 

Thiocyanic  A  cid. — Colasanti — Ellram. 

Thiophen. — Deniges — Meyer. 

Tin  (Salts  of). — Deniges — Rogiers. 

Turpentine  Oil. — Fabris. 

Toluidine. — Wolff. 

Tyrosine. — Deniges  —  Hoffmann  —  Piria,  Staedeler 
— Scherer — Udranszky — Wurster. 


U. 

Uranium  (Salts  of). — Crolas,  Ducker. 

Urea. — Hiiffner,     Knopp  -  -  Liebig  -  -  Schiff  - 

Yvon. 

Ur  ethane. — Jacquemin. 
Uric  Acid. — Deniges  —  Dieterich  —  Focker  — 

Gigli  —  Jaksch  —  Offer  —  Riegler  —  Schiff. 
Urine. — Abelin  —  Agostini  —  Almen  —  Alpers  - 

Amand  —  Arnold  —  Biffi  —  Bischoff  —  Bodecker 

—  Bottger  —  Campani  —  Capranica  —  Carrez  — 
Chautard  —  Christensen  —  Cohen  —  Crismer  - 
Criswell  —  Crouzel  —  Cunisset  —  Daclin  —  Day 
— Degener  —  Deniges  — Desesquelle  —  Devoto— 
Donogany  —  Dragendorff  —  Drechsel  —  Ebstein, 
Miiller  —  Ehrlich  —  Eiselt  —  Ellram  —  Esbach 

—  Fehling  —  Fleischl  —  Focker  —  Frohde  - 
Furbringer  --  Galippe  --  Gallois  --  Gand  - 
Gerhardt  —  Gerrard  —  Gluzinsky  —  Gmelin  - 
Guerin  —  Hammarsten  —  Heller  --  Hilger  - 
Hoppe      Seyler  -  -  Hiifner  -  -  Hiihnenfeld  - 
Huppert   -  -   Ihl   -  -  Jaksch   -  -   Jaquemin   - 
Jaworowsky  —  Johnson  —  Jolles  —  Kathrein  - 
Kerner  —  Klett  —  Knopp  —  Krehbil  —  Kulz  - 
Lechini  —  Legal  —  Le  Noble  -  -  Leismer  — 
Lieben  —  Liebermann  —  Liebig  —  Lowenthal  - 

212 


COLLECTIVE   INDEX. 

Lugol  —  MacMunn  —  Mac  William  —  Marechal 

-  Mehu  -  -  Messinger  -  -  Muller  -  -  Mylius  — 
Neebauer  —  Nencki  —  Nylander  —  Obermayer 

-  Oudreyovich  -  -  Panum  —  Paul  —  Pavy  — 
Pentzold  —  Pettenkofer  —  Possner  —  Prosch  — 
Raabe  —  Riegler  —  Roman,   Delluc  —  Rose  — 
Rosenbach  -  -  Rosin  -  -  Sadlund  —  Saillet  — 
Salkowski  —  Schaffer  —  Schiff  —  Schlesinger  — 
Schmidt  -  -  Smith  -  -  Soldaini  —  Spiegler  - 
Struve  —  Strzyzowscky  —  Tanret  —  Thormah- 
len  -      Tollens  -  -  Trommer  -  -  Udranszky  — • 
Ultzmann  —  Vitali  —  Weber  —  Weyl  —  Yvon — 
Zulser. 

Urobilin. — Jaffe  —  Roman,  Delluc  —  Schmidt. 
Urobilinogen. — Saillet. 

V. 

Vanadates. — Mitchell. 

Vanillin. — Bonnema — Moerk — Nickel. 

Vaseline. — Crouzel. 

Veratrine. — Ferraro  -  -  Lave  -  -  Schumpelitz 

Thomson — Tr  app — Weppen . 
Veronal. — Molle. 

W. 

Wax. — Donath. 

Wine. — Arata  --  Blarez  —  Bottger  —  Brand  — 
Carpene  —  Cazeneuve  —  Cottini,    Fantogini  - 
Debrun  —  Faure  —  Girard  —  Sangle,  Ferriere  — 
Sanna,  Pintus. 

X. 

Xanthin. — Hoppe  Seyler — Weidel. 

Z. 

Zinc  (Salts  of). — Rinnmann. 
213 


REAGENTS  AND   REACTIONS. 


TABLE  I. 
INTERNATIONAL   ATOMIC   WEIGHTS. 


Element. 

Sym- 
bol. 

Atomic 
Weight. 

Element. 

Sym- 
"bol. 

Atomic 
Weight. 

Aluminium     . 

Al 

27-1 

Neodymium  . 

Nd 

i44'3 

Antimony 

Sb 

I2O-2 

Neon    . 

Ne 

20-2 

Argon    . 

A 

39-88 

Nickel 

Ni 

58-68 

Arsenic  . 

As 

74-96 

Niton          (radium 

Barium 

Ba 

137-37 

emanation) 

Nt 

222-4 

Bismuth 

Bi 

208-0 

Nitrogen 

N 

I4-OI 

Boron    . 

B 

II-O 

Osmium 

Os 

190-9 

Bromine 

Br 

79-92 

Oxygen 

0 

16-00 

Cadmium 

Cd 

112-40 

Palladium     . 

Pd 

106-7 

Caesium  . 

Cs 

132-81 

Phosphorus  . 

P 

31-04 

Calcium 

Ca 

40-07 

Platinum 

Pt 

195-2 

Carbon  . 

C 

12-005 

Potassium    . 

K 

39-10 

Cerium  . 

Ce 

140-25 

Praseodymium 

Pr 

140-9 

Chlorine 

Cl 

35-46 

Radium 

Ra 

226-0 

Chromium 

Cr 

52-0 

Rhodium 

Rh 

102-9 

Cobalt   . 

Co 

58-97 

Rubidium     . 

Rb 

85-45 

Columbium     . 

Cb 

93-i 

Ruthenium  . 

Ru 

101-7 

Copper  . 

Cu 

63-57 

Samarium     . 

Sa 

150-4 

Dyprosium 

Dy 

162-5 

Scandium 

Sc 

44*i 

Erbium  . 

Er 

167-7 

Selenium 

Se 

79-2 

Europium 

Eu 

152-0 

Silicon  . 

Si 

28-3 

Fluorine 

F 

19-0 

Silver  . 

Ag 

107-88 

Gadolinium    . 

Gd 

157-3 

Sodium 

Na 

23-00 

Gallium  . 

Ga 

69-9 

Strontium     . 

Sr 

87-63 

Germanium    . 

Ge 

72-5 

Sulphur 

S 

32-06 

Glucinum 

Gl 

9-1 

Tantalum 

Ta 

181-5 

Gold      . 

Au 

197-2 

Tellurium 

Te 

127-5 

Helium  . 

He 

4-00 

Terbium 

Tb 

159-2 

Holmium 

Ho 

163-5 

Thallium 

Th 

204-0 

Hydrogen 

H 

1-008 

Thorium 

Th 

232-4 

Indium  . 

In 

114-8 

Thulium 

Tm 

168-5 

Iodine    . 

I 

126-92 

Tin       . 

Sn 

118-7 

Iridium  . 

Ir 

I93'i 

Titanium 

Ti 

48-1 

Iron 

Fe 

55-84 

Tungsten 

W 

184*0 

Krypton 

Kr 

82-92 

Uranium 

U 

238-2 

Lanthanum    . 

La 

139-0 

Vanadium     . 

V 

51-0 

Lead      . 

Pb 

207-20 

Xenon  . 

Xe 

130-2 

Lithium 

Li 

6-94 

Ytterbium      (Neo- 

Lutecium 

Lu 

175-0 

ytterbium) 

Yb 

i73'5 

Magnesium     . 

Mg 

24-32 

Yttrium 

Yt 

88-7 

Mercury 

Hg 

200-  6 

Zinc     . 

Zn 

65-37 

Molybdenum  . 

Mo 

96-0 

Zirconium     . 

Zr 

90-6 

214 


TABLES. 


TABLE  II. 
AQUEOUS  SOLUTIONS   OF  AMMONIA 

(LUNGE-WlERNIK). 

SPECIFIC  GRAVITY  AT  15°  C.  COMPARED  WITH 
WATER  AT  15°  C.  =  i. 


Sp.gr. 

NH3 
%• 

i  litre 
contain- 
ing at 
15°  C. 
grins. 

Correc- 
tion per 

+  r  C. 

Sp.  gr. 

NH 

%. 

i  litre 
contain- 
ing at 
15°  C. 
grms. 

Correc- 
tion per 
+  i°C. 

I  -000 

o-oo 

o-o 

0-00018 

0-940 

15-63 

146-9 

0-00039 

0-998 

o-45 

4'5 

o-ooo  i  fc 

0-938 

16-22 

152-1 

0-00040 

0-996 

0-91 

9-1 

0-00019 

0-936 

16-82 

157-4 

0-00041 

0-994 

i-37 

i3'6 

0-00019 

0-934 

17-42 

162-7 

0-00041 

0-992 

1-84 

18-2 

O-OOO20 

0-932 

18-03 

168-1 

0-00042 

0-990 

2-31 

22-9 

0-00020 

0-930 

18-64 

173-7 

0-00042 

0-988 

2-80 

27-7 

0-00021 

0-928 

19-25 

178-6 

0-00043 

0-986 

3-30 

32'5 

O-OOO2I 

0-926 

19-87 

184-2 

0-00044 

0-984 

3-80 

37-4 

O-OO022 

0-924 

20-49 

189-3 

0-00045 

0-982 

4-30 

42-2 

0-00022 

0-922 

21-12 

194-7 

0-00046 

0-980 

4-80 

47-0 

0-00023 

0-920 

21-75 

200-  1 

0-00047 

0-978 

5-30 

51-8 

0-00023 

0-918 

22-39 

205-6 

0-00048 

0-976 

5'8o 

56-6 

O-OOO24 

0-916 

23-03 

210-9 

0-00049 

0-974 

6-30 

61-4 

O-OOO24 

0-914 

23-68 

216-3 

0-00050 

0-972 

6-80 

66-1 

O-OOO25 

0-912 

24-33 

221-9 

0-00051 

0-970 

7-3i 

70-9 

0-00025 

0-910 

24-99 

227-4 

0-00052 

0-968 

7-82 

75-7 

O-OOO26 

0-908 

25-65 

232-9 

0-00053 

0-966 

8-33 

80-5 

O-OOO26 

0-906 

26-31 

238-3 

0-00054 

0-964 

8-84 

85-2 

O-OOO27 

0-904 

26-98 

243-9 

0-00055 

0-962 

9-35 

89-9 

O-OOO28 

0-902 

27-65 

249-4 

0-00056 

0-960 

9-91 

95*1 

0-00029 

0-900 

28-33 

255-0 

0-00057 

0-958 

10-47 

100-3 

O-OOO3O 

0-898 

29-01 

260-5 

0-00058 

0-956 

11-03 

105-4 

O-OOO3I 

0-896 

29-69 

266-0 

0-00059 

0-954 

ii«6o 

110-7 

O-OO032 

0-894 

30-37 

27i-5 

0-00060 

0-952 

12-17 

"5-9 

0-00033 

0-892 

31-05 

277-o 

0-00060 

0-950 

12-74 

I2I-O 

0-00034 

0-890 

31-75 

282-6 

0-00061 

0-948 

i3-3i 

126-2 

0-00035 

0-888 

32-50 

288-6 

0-00062 

0-946 

13-88 

I3I-3 

O-OOO36 

0-886 

33-25 

294-6 

0-00063 

0-944 

14-46 

I36-5 

0-03037 

0-884 

34-10 

301-4 

0-00064 

0-942 

15-04 

I4I-7 

O-OOO38 

0-882 

34-95 

308-3 

0-00065 

215 


REAGENTS  AND   REACTIONS. 


ffl  £ 
w° 


w 
o 
fc 


« "« 

!! 


CO 


O 

HH       ^ 

a  H 

CO 

w    ^ 

»-3      •< 
«     O 


p 

(-1 
o 

CO 


o  9  9"10?  ^''P  ^  ^ 
£-0000  0\0  M  <M  ro 


oo  M  ro  ^\o  01  N  m 


>   -tNOO    O>  6    Ot    CO  ^-  UO  fxOO    C\O    M    CO^t-u-jt- 

•)COCOCOTl-^T*-ThTl-Tj-Tt-THOlOlO«0>nW 


OOO  t"xtOfOCON    QOO   t 


-^-«O<O»n>O<O   >O«OVD  INOO    O    C 
N    COTj-iuO^OtNob    ^O    M    N    COThiXiko 
OCOCOCOCOCO  CO  To  CO  5*-  5-  ^-  ?  *  1?  ^° 


^•vp  op  O   ^-vo  9   ^-O   7»-9^0   ^-9opvOvOVOvpvpOO  9   avo   0   ^OOO 

6  N  *KOkw  ^-^o  a*  H  ^-vo  a>  N  Tt-fN  b  covb  c?icjvb  eifjvb  a\rovo 
«n«oio«o'o^Dvo^ovo  tN^^stNoo  oooo  c^chc^cno  o  o  MM  HWW 


N   CO^->Ot>«OO    O   N>OtNO   COtNO    ^i-QO   tOOO    fOOO   rhOvO   fOO^N>O 
•OVOtNOO    C^O    a   CO  T*-«r>  txoo    ChM    N    fOiDOOO    OiM    CO  T*-VO  OO    Oi  M    C 
C*   N    N    d   N    COCOCOCOCOCOCOCOTl-Tj-^-^-rJ-Tl-TJ-u-ju-jxoiOiO  «OVO  V 


O  M  W  CO  •*  >OVO  tSOO  Oi  O  O  N  N  CO  Tj-  >OVO  ^XOO  O\  O  M  N  CO  rt- 


O    H    N    C*    CO  Tt"  IOVO  VOtXOO    C^O    O    M    W    COCOxJ-lOVOtNOOOO    OlO    H 


MC4-*«OtNC7\Or<    CO  «OVO  CO    O 


Turjvbcb    6    04    Tj-«O  00    6    0<    Aj-VO  O 


HHHHHHHHMHNNtMNNNN 


o  o  o  o  o°  o"  o^'o  V99C99>2MMM[?H"h?H> 


216 


TABLES. 


K 

Sse 
^ 

^  ?5  ^-Vo"iO  00  CO  CO5  °    ^  ^  ^   ^  ^^    *°  ^  °    °^  H    ^^    *°  °    N 
ON  O    M    N    CO  T»-  iovb  Kcb    Oi  H    04    CO  V^O  txOO    Oi  H    N    ii-vb  fs  ON 

w 

0 

5 
y 

o  . 

fr* 

CJ 

I! 

0««*VOOOO*VOO*0*0«^OOOVOVOOVOVOOOO 

0 

m 

H 

ll 

Tj-^^->O>oioio«OVOvOVO'OfNtNtX'tNCOCOOO   OiONONOiO   O 
H    H 

H 
< 

Ii 

< 
P 

aj  rt 
QCQ 

O 

in 

*'  y 

5 

s-aws^gasftRsss^ss**** 

£  H 
«  £ 

f 

£< 

H  U 

O^o 

voc^o^coOvp^.op.proovo:j-OO^opOlncoMONtNvp<?o 

fa 

o 

Z 

CO 

^ 

0    . 

txcomOOOOO  moo  tNOcoOOOOOOO^cOfOOOO 

O 

t—  1 
f    , 

go 

B 

h-1 

IJ 

O 

CO 
CO 

IJ 

„    „    „    „    H    H    N    C<    «    M    M    C*    CO  CO  CO  CO  CO  ^  5- 

D 

O 

aj  »aJ 

S6 

p 

a 

O)   03 

QCQ 

< 

|j 

O 

OOOOOOOOOOOMMMHMMMMHMMNN 

217 

REAGENTS  AND   REACTIONS. 


TABLES  V.  AND  VI. 

POTASSIUM   CARBONATE   AT   15°  C. 

(GERLACH). 


Sp.  Gr. 

K2C03 

%- 

Sp.  Gr. 

K2CO3 

%- 

Sp.  Gr. 

K2C03 
%. 

1-00914 

i 

1-18265 

19 

1-38279 

37 

•01829 

2 

1-19286 

20 

1-39476 

38 

•02743 

3 

1-20344 

21 

1-40673 

39 

•03658 

4 

1-21402 

22 

1-41870 

40 

•04572 

5 

1-22459 

23 

1-43104 

4i 

•05513 

6 

1-23517 

24 

i'44338 

42 

•06454 

7 

1-24575 

25 

1-45573 

43 

•07396 

8 

1-25681 

26 

1-46807 

44 

•08337 

9 

1-25787 

27 

1-48041 

45 

•09278 

10 

1-27893 

28 

I-493I4 

46 

•10258 

ii 

1-28999 

29 

1-50588 

47 

•11238 

12 

1-30105 

30 

1-51861 

48 

•12219 

13 

1-31261 

31 

I-53I35 

49 

•13199 

14 

1-32417 

32 

I-54408 

50 

•14179 

15 

1-33573 

33 

1-55728 

51 

•15200 

16 

1-34729 

34 

1-57048 

52 

•16222 

17 

I-35885 

35 

1-57079 

51-024 

•17243 

18 

1-37082 

36 

SODIUM   CARBONATE  AT  15°  C.    (LUNGE). 


Sp.  Gr. 

Baume. 

Twaddell. 

NaaCOa 

Na2CO3  +  ioH2O 

•007 

i 

i'4 

0-67 

1-807 

•014 

2 

2-8 

i-33 

3-587 

•022 

3 

4'4 

2-09 

5*637 

•029 

4 

5-8 

2-76 

7-444 

•036 

5 

7-2 

3-43 

9-251 

•045 

6 

9-0 

4-29 

ii-57o 

•052 

7 

10-4 

4'94 

13-323 

•060 

8 

I2-O 

5-71 

15-400 

•067 

9 

I3'4 

6-37 

17-180 

•075 

10 

15-0 

7-12 

19-203 

•083 

ii 

16-6 

7-88 

21-252 

•091 

12 

18-2 

8-62 

23-248 

•100 

*3 

20-0 

9'43 

25-432 

•108 

14 

21-6 

10-19 

27-482 

•116 

15 

23-2 

10-95 

29-532 

•125 

16 

25-0 

ll-fil 

31-851 

•134 

17 

26-8 

12-61 

34-009 

•142 
•152 

18 
19 

28-4 
30-4 

13-16 

14-24 

35-493 
38-405 

218 


TABLES. 


TABLES  VII.  AND  VIII. 
HYDROCHLORIC   ACID 

(KOLB). 


Sp.  Gr. 

HC1 

Sp.  Gr. 

HC1 

Sp.  Gr. 

HC1 

Sp.  Gr. 

HC1 

ati5°C. 

%- 

at  15°  C. 

%• 

at  15°  C. 

%- 

at  15°  C. 

% 

•007 

i'3 

1-067 

I3-4 

•134 

26-6 

1-180 

35-7 

•014 

2-9 

1-075 

15-0 

•143 

28-4 

1-185 

36-8 

•023 

4'5 

1-083 

16-5 

•152 

30-2 

•190 

37-9 

•029 

5'8 

1-091 

18-1 

•157 

31-2 

•195 

39-0 

•036 

7-3 

I-IOO 

19-9 

•161 

32-0 

•199 

39-8 

•044 

8-9 

1-108 

21-5 

•166 

33*0 

•205 

41-2 

•052 

10-4 

1-116 

23-1 

•171 

33'9 

•2IO 

42-4 

•060 

I2-O 

1-125 

24-8 

•175 

34'7 

I-2I2 

42-9 

NITRIC  ACID 

(KOLB). 


Sp.  Gr. 
it  15°  C. 

HNOg 

Sp.  Gr. 
at  15°  C. 

HNO3 

Sp.  Gr. 
at  15°  C. 

HN03 

Sp.  Gr. 
at  15°  C. 

HNO3 

1-007 

i-5 

•108 

18-0 

1-231 

37-0 

1-384 

61-7 

1-014 

2-6 

•116 

19-4 

•242 

38-6 

1-398 

64-5 

I-O22 

4-0 

•125 

20-8 

•252 

40-3 

1-412 

67'5 

I-O29 

*I34 

22-2 

•261 

4i*5 

1-426 

70-6 

1-036 

6-3 

•143 

23-6 

•275 

43-5 

1-440 

74-4 

•044 

7-6 

•152 

24-9 

•286 

45*0 

1-454 

78-4 

•052 

9-0 

•161 

26-3 

•298 

47-1 

1-470 

83-0 

•060 

10-2 

•171 

27-8 

•309 

48-6 

1-485 

87-1 

•067 

11-4 

•180 

29-2 

•321 

50-7 

1-501 

92-6 

•075 

12-7 

•190 

30-7 

•334 

52-9 

1-516 

96-0 

•083 

14-0 

•199 

32-1 

•346 

1-524 

98-0 

•091 

I5'3 

•210 

33-8 

•359 

57-3 

1-530 

IOO-O 

•100 

16-8 

•221 

35-5 

•372 

59'6 

219 


REAGENTS  AND   REACTIONS. 


pure  acid 
per  kilo. 

O 

MMMHMMMMMHMMMHHMHMHMHMMHMM 

<u  as 
§fl 

^H     O 

i 

f^OtXNMOOVO   -rhCOH   O>OO  .TxVO   <O  >O  Ti-OO   C>  -tx  lOOO   O  VO  OO   «O 

H    « 

|l 

>.!2~ 

o 
E 

VO   <NtstXtNtSlX^Nt>s^tNt>.  tNOO  OOOOOOOOOOOQOO    O>O^OO>O 
H 

W 

§ii 
0 

g 

OOO^O>OHMtN^OOCO  Tj-VO  00    O    M  00  VO    M-00    M    1O  ^-  O^  O 

C/) 
I-H 

W 

o 

II 

,  1 

x' 

I—I 

£ 

*v 

j 

OOOOOOOOOOOOOOOOOOOOOOOOnN 
M   C*   CO  TJ-  1OVO  fxOO    O>  O    M    O>    CO  TJ-  lOVO   IXOO    O^iO    M    M    COrJ-Tj-rh 
OVOVOVOVOVOVOVOVO    tNt^tXlNtNtXlNtXlS  tNOO  00  OO  OO  OO  00  OO 

W 

Q 

>—  i 

cfl      ° 

N 

h-1 

3 

u 

I-H 

pure  acid 
per  kilo. 

1 

HOOVO    HVO    M    COtNOO    OiCOtNM    QOO    ^NOO    CON    WOOVOtxiO^-VO 

bbbbbbbbbbbbbbbobbbbbbbbMMH 

D 

i  litre  of 
contains 

1 

H    tN  CO  >OOO    txVO  VO    O\  N    CO  O  00    COOO    ^tNlN10O\OiO>H    MtNH    1O 
OOOOOOOOHHMNOJNHNCO^IOIO  10  VO    K  INOO  00  OO 

bbbbbbbbbbbbbbbbbbbbbbbbbbb 

& 

CO 

fg 
Is 

O 

O  oo  10  O  ^vo  <N  Oi  covo  vo  H  IN  o  cooo  c»  «OO>>OH  IOIN«OT*-|X«O 

w 

HHHHO,C,NNNCO^^^^^^VOVOVO 

||" 

S5 

INOO  OO   IX  INVO    lOOHWWMMVOOVONOONNVOHCO  -<1-VO  VO    CO 
O  VO    04    rhVO    TtMCMxrJ-OHNncO  COVO  OO    COVO  IX  CO  IN  O    Tj-  n-  O\ 

o 

o 

b  b  H  oi  co  vr>  f>oo  M  Vvb  ob  b  H  n  rj-  o\  cooo  bi  H  u-job  M  co  V-  «o 

2*0 

(A 

il 

0    K  ^  IN  H    0    0    0    0    0   IS  00    0    0    0    0    H    0    0    H    0    H    H    0    H    0    H 

OJD  2 

Q« 

M.    c 

j 

f 

OioOOO<OO>OOioOOOOOO«OOO«OO>OOOMOOH 
O   O   M   o»  CO  ri-vo  -K  O   01   rt-vo  OO   ON  O   N  VO   M  INOO   H   10  w   'OVO  OO   O 

C/}       ° 

0 

220 


TABLES. 


CJ 


vO 

H 


O    o 

K  Q, 


op 


CO 

H 


o 
o 

HH 

fe 

HH 

CJ 

W 

CO 


O 
PL, 

a 


§ 


MOO   ^"  O  O   MOO   ^  O 
iO  t"^  O   CO  !OOO   O   CO  vO 

-  C-.CQ    ON  6   O   M   M   M   CO 


t^-CO   ON  O 


MM     Tt-VOC^CO 

COM    O\t^iO^M    M    (^00    I^VO    iOrJ-CO(MMOOON 
t^OO  OO^OMMCOCOrJ-  iO»O    t^OO    ON  O    w   M    CO  CO 


VO   MOO    "*•  O  O    MOO    Tj-  O  O    MOO    rt-  O  O   MOO    ^O 

•^•^•ONM  »o  i>- o  M  1000  o  co  »oo  M  coo  oo  M  TJ- 

M  ONO  rf  M  op  O  CO  9  ^Y^N  CO  7^M°p  'PT^P 
iO  !OO  t^OO  CO  ON  O  M  M  M  CO  CO  ^"  !OO  O  t^OO  ON 
MMMMMMMMMMMMMMMMMMMM 


M   M   CO  Tj-  IOVO   t^OO   ON  O   M   M   CO  ^f  lOO   C^OO   O>  O 
M   M   M   M   M   M   M   M   M    COCOCOCOCOCOCOCOCOCOTr 


. .  _ . ,  - ...MOMOO^OCOMM 

(5  O   M   ON  O   CO  O   Is*  ^  M  00  O   CO  M  OO  O   CO  M   ON  C^  *O 

M   CO  CO  Tj-  iOO  O   t^OO  00    ONQ   H   w    M    cO^t"'^'lOO 

O   MOO    ^"OO   MOO    ^OO   MOO    ^OO   MOO    "^"O 
M   «O  1^  O   CO  u-iOO    O   COO  CO   M   COO    ON  M    Tf  O   ON  M 
C^«  "<4"  M   ON  O  co  O  OO  u")  M   ON  t^  ^~  M  CO  O  co  O   ''"^  lf^ 
e*  M   M   M   M   CO  rt-  ir>  vOO   f>.  C^OO 

K 

M   CO  ^  >OO   C^OO   ON  O   w   M   CO  ^J*  ^OO   t^OO   ON  O 

f  ON  ^  O  O  CO  O  ONOO   t^.  t^OO   ONM   Tfl^M  inOO 
O  !OOOMJ>*COON^t-OOMOOTj-Ml>.cOQOrOON 

^MMMMCOCOTfiO  »OO  O   t^CO  00   ON  O   O   w   M 


221 


REAGENTS  AND   REACTIONS. 


IN 

o  . 
o 

txoo  cnc  M  N  co-<r«nvo  fxoo  <^  o  H  N  co  •*  «o\o  <NQO  o\  o 

tS  ^  tSOO  OOOOOOOOCX30OOOOOOO    C^dCriC7\aiO\O\a><^O^O 

u 

u 

p, 

C/3 

9999999999o'99X99VpvoV9Vovo(p*p95o> 

O    . 

§^ 

N    CO  •<*•  >OVO  fsOO    O\O    H   W   COrHOVO  txOO    O\O   M    N   CO^iO^O 

H 

d 

9999999999999999999999900 

$'. 

§ 

5 

o  o  o  o  o  o  o  o  o  o  o  o  o.o  oooooooooooo 

C/3 

O    . 

§ 

i4 

O 

ft 

M   tN  N   t"x  OJ   fN  COOO    CO  fS  N   tS  H   1O  O    ^OO    N  VO    O    ^*-OO    M    ^*-  tx  O 
O\O    04    CO«OVOOO    ^M    CM    >*-«O  tXOO    O    HW    '^•'OIXOO    C\MNCO»O 

O\OOOOOOOOOOOOOOOOO9OOOOOOO 

222 


TABLES. 


TABLE  XII. 
METHYL  ALCOHOL   (DITTMAR-FAWSITT). 


%by 
Weight. 

Sp.  Gr. 
ato°C. 

Sp.  Gr. 
at  15-56°  C. 

%by 
Weight. 

Sp.  Gr. 
at  o°  C. 

Sp.  Gr. 
at  15-56°  C. 

I 

0-99806 

0-99729 

63 

0-90276 

0-89133 

2 

0-99631 

0-99554 

64 

0-90056 

0-88905 

4 

0-99299 

0-99214 

65 

0-89835 

0-88676 

6 

0-98990 

0-98893 

66 

0-89611 

0-88443 

8 

0-98701 

0-98569 

67 

0-89384 

0-88208 

10 

0-98429 

0-98262 

68 

0-89145 

0-87970 

12 

0-98171 

0-97962 

69 

0-88922 

0-87714 

14 

0-97926 

0-97668 

70 

0-88687 

0-87487 

16 

0-97689 

0-97379 

7i 

0-88470 

0-87262 

18 

0*97459 

0-97039 

72 

0-88237 

0-87021 

20 

0-97233 

0-96808 

73 

0-88003 

0-86779 

22 

0-97007 

0-96524 

74 

0-87767 

0-86535 

24 

0-96780 

0-96238 

75 

0-87530 

0-86290 

26 

0-96549 

0-95949 

76 

0-87290 

0-86042 

28 

0-96310 

0-95655 

77 

0-87049 

0-85793 

30 

0-96057 

0-95355 

78 

0-86806 

0-85542 

32 

0-95783 

0-95053 

79 

0-86561 

0-85290 

34 

0*95500 

0-94732 

80 

0-86314 

0-85035 

36 

0-95204 

0-94399 

81 

0-86066 

0-84779 

38 

0-94895 

0-94055 

82 

0-85816 

0-84521 

40 

0-94571 

0-93697 

83 

0-85504 

0-84262 

42 

0-94239 

0-93335 

84 

0-85310 

0-84001 

44 

0-93911 

0-92975 

85 

0-85055 

0-83738 

46 

0-93575 

0-92610 

86 

0-84798 

0-83473 

48 

0-93229 

0-92237 

87 

0-84539 

0-83207 

50 

0-92873 

0-91855 

88 

0-84278 

0-82938 

5i 

0-92691 

0-91661 

89 

0-84015 

0-82668 

52 

0-92507 

0-91465 

90 

0-83751 

0-82396 

53 

0-92320 

0-91267 

9i 

0-83485 

0-82I23 

54 

0-92130 

0-91066 

92 

0-83218 

0-81849 

55 

0-91938 

0-90863 

93 

0-82948 

0-81572 

56 

0-91742 

0-90657 

94 

0-82677 

0-81293 

57 

0-91544 

0-90450 

95 

0-82404 

0-8IOI3 

58 

0-9I343 

0-90239 

96 

O-82I29 

0-80731 

59 

0-91139 

0-90026 

97 

0-81853 

0-80448 

60 

0-90917 

0-89798 

98 

0-81576 

0-80164 

61 

0-90706 

0-89580 

99 

0-81295 

0-79876 

62 

0-90492 

0-89358 

IOO 

O-8IOI5 

0-79589 

223 


REAGENTS   AND   REACTIONS. 


TABLE  XIII. 
ETHYL  ALCOHOL. 

PERCENTAGE  OF  ALCOHOL  BY  VOLUME  AND 
SPECIFIC  GRAVITY  COMPARED  WITH  WATER 
AT  15°  C. 


Alcohol  %. 

Sp.  Gr. 

Alcohol  %. 

Sp.  Gr. 

Alcohol  %• 

Sp.  Gr. 

I 

0-99844 

35 

0-95923 

69 

0-89274 

2 

0-99695 

36 

0-95786 

70 

0-89029 

3 

0-99552 

37 

0'95645 

71 

0-88781 

4 

0-99413 

38 

0-95499 

72 

0-88531 

5 

0-99277 

39 

0-95350 

73 

0-88278 

6 

0-99I45 

40 

0-95196 

74 

0-88022 

7 

0-99016 

4i 

0-95020 

75 

0-87763 

8 

0-98891 

42 

0-94872 

76 

0-87500 

9 

0-98770 

43 

0-94705 

77 

0-87234 

10 

0-98652 

44 

0-94535 

78 

0-86965 

ii 

0-98537 

45 

0-94361 

79 

0-86692 

12 

0-98424 

46 

0-94183 

80 

0-86416 

13 

0-98314 

47 

0-94002 

81 

0-86137 

M 

0-98206 

48 

0-93817 

82 

0-85854 

15 

O-gSlOO 

49 

0-93629 

83 

0-85567 

16 

0-97995 

50 

0-93437 

84 

0-85275 

17 

0-97892 

5i 

0-93241 

85 

0-84979 

18 

0-97790 

52 

0-93041 

86 

0-84678 

19 

0-97688 

53 

0-92837 

87 

0-84372 

20 

0-97587 

54 

0-92630 

88 

0-84060 

21 

0-97487 

55 

0-92420 

89 

0-83741 

22 

0-97387 

56 

0-92209 

90 

0-83415 

23 

0-97286 

57 

0-91997 

91 

0-83081 

24 

0-97185 

58 

0-91784 

92 

0-82738 

25 

0-97084 

59 

0-91569 

93 

0-82385 

26 

0-96981 

60 

0-91351 

94 

O-82020 

27 

0-96876 

61 

0-91130 

95 

0-81641 

28 

0-96769 

62 

0-90907 

96 

0-81245 

29 

0-96659 

63 

0-90682 

97 

0-80829 

30 

0-96545 

64 

0-90454 

98 

0-80390 

3i 

0-96428 

65 

0-90224 

99 

0-79926 

32 

0-96307 

66 

0-89991 

100 

0-79433 

33 

0-96183 

67 

0-89755 

— 

— 

34 

0-96055 

68 

0-89516 

224 


TABLES. 


TABLE  XIV. 
ETHYL   ALCOHOL. 

SPECIFIC  GRAVITY  AND  PERCENTAGE  BY  VOLUME 
AT  I5'05°C. 

WATER  =  0-9991  (TRALLES). 


Vol.  % 
Alcohol. 

Sp.  Gr. 

Vol.  % 
Alcohol. 

Sp.  Gr. 

Vol.  % 
Alcohol. 

Sp.  Gr. 

I 

0-9976 

35    0-9583 

69 

0-8917 

2 

0-9961 

36 

0-9570 

70 

0-8892 

3 

0-9947 

37 

0-9559 

71 

0-8867 

4 

0-9933 

38 

0-9541 

72 

0-8842 

5 

0-9919 

39    0-9526 

73 

0-8817 

6 

0-9906 

40   i  0-9510 

74 

0-8791 

7 

0-9893 

41 

0-9494 

75 

0-8765 

8 

0-9881 

42 

0-9478 

76 

0-8739 

9 

0-9869 

43 

0-9461 

77 

0-8712 

10 

0-9857 

44 

0-9444 

78 

0-8685 

ii 

0-9845 

45 

0-9427 

79 

0-8658 

12 

0-9834 

46 

0-9409 

80 

0-8651 

13 

0-9823 

47 

0-9391 

81 

0-8603 

M 

0-9812 

48 

0-9373 

82 

0-8575 

15 

0-9802 

49 

0-9354 

83 

0-8547 

16 

0-9791 

50 

0-9335 

84 

0-8518 

17 

0-9781 

5i 

0-93I5 

85 

08488 

18 

0-9771 

52 

0-9295 

86 

0-8458 

19 

0-9761 

53 

0-9255 

87 

0-8428 

20 

0-9751 

54 

0-9245 

88 

0-8397 

21 

0-9741 

55 

0-9234 

89 

0-8365 

22 

0-9731 

56 

0-9213 

90 

0-8332 

23 

0-9720 

57 

0-9192 

9i 

0-8299 

24 

0-9710 

58 

0-9170 

92 

0-8265 

25 

0-9700 

59 

o  9148 

93 

0-8230 

26 

0-9689 

60 

0-9126 

94 

0-8194 

27 

0-9679 

61 

0-9104 

95 

0-8157 

28 

0-9668 

62 

0-9082 

96 

0-8118 

29 

0-9657 

63 

0-9059 

97 

0-8077 

30 

0-9646 

64 

0-9036 

98 

0-8034 

31 

0-9634 

6< 

0-9013 

99 

0-7988 

32 

0-9622 

66 

0-8989 

100 

0-7939 

33 

0-9609 

67 

0-8695 

— 

34 

0-9596 

68 

0-8941 

— 

— 

225 


15 


REAGENTS   AND   REACTIONS. 


03 

q 

a 


C/3 

W 


W 


W  ^ 

W  W 

>-"        tD  •—» 

^    o  w 

<J      H  H 

PH  W 

<  o 


§ 

o 

g 


§ 
& 

> 
« 

o 


ui 


CO 


ON  O  OJ  0»   COCO  M   CO  t^  O 

t^-CO    ON^*M   C^  vowoo    M 

IOVO  00    M    rf  vO  t^OO 
ONOO   t>>  t>  ~ 


rJ-cON   H   O   ONOO    t>*iOT}-cOC-!   O   ON  CO 
ON  ON  O  ON  ONCO  OOOOOOCpCpOpOO    ^*  ^ 

666666666666666666666 


-H     COO     IOONM     M     QO     1O  M     COIO 

CO  rt-  ON  M  t^OO  O  w  w  ONO  t^NOOOOOVO  M  O  co^ 
00  ON  M  lOOO  M  TfiOiO-^-Tj-CI  H  ONl>-iOCOMOO  "*$•  O~> 
ONOO  CO  J>.vO  Oin-^cOMMOON  l>«v£>  in  ^  CO  M  Q  00 
ONONONONONONONONONONON  ONOO  OOOOOOOOOOOOOO 


666666666666666666666 


U~>  CO  ONVO    COC^CO    ' 
t^M   O   M  vO    t^ON 
ON  M    ^00   NOON 
ON  ONOO    I>-  1 


-ONM   N   H-vOO    ONOO 
N  I>-O    "*•  N    ON^O   01    t-^ 
M    ONOO    1>-O    iO  CO  M   M    ON 


ooooooooooooooooocooo 


00    u~>  CO  'OO   iO  O    ^  ON  t^  O  CO    c->    iO  O   ' 

ON  ONOO    J>.  t^  I>»vO   iO  Tf  CO  N   M   O   ONOO    I>.vO    Tj-  CO  N   O 
ONONONONONONONONONONONONONOOOOOOOOOOOOOOOO 

666666666666666666666 


>O  O  >OO  i 
--<fiO  »OO 


O  »O  O  "^  O  ^ 
t^  t^CO  00    ON  ON 


226 


TABLES. 


vO    ^t-  CO  <N    p  op    £>-O    Tf  CO  <N    p 
00  CO  CO  CO  GO   C^-  I>»  r*"  t^  t>»  •>>•  C^ 


.  iO  ^-  CO  W    O 


^O'^^Ot>-lOO'>«>^^Ol 
Tf  CO  w   O    &  1^*0    >O  CO  <S    M    O  C 


iO  CO  N    O    O<X __._        .... 

rOrororoc^c^C^MMNMC^MMHHMMMMi. 
NNNNNNNNNNNNNNNNNNNNN 


tf 

w 
KH 


N  6  6  M 

NNN 


o 


vp   «O  CO  N   9   O^Op   t>. 
O^O^^^  ON  CO  CO  CO 


o 

& 

(A 


O   >0  N 

Tj-  M     M 


| 

^ 


v6   f^  t^.00  CO   ON  CN  6  6 


227 


REAGENTS   AND    REACTIONS. 


U 


^ 


S  w 
<   o 


XI 

w 

Q 


^~  O  O  M  O  ^t-  O  *O  O  u~;  O  ^f  r^  O  co  10  r^oo 
M  l>»  CM  OO  CO  0^  LO  O  O  >— '  t^  CM  l^  ""O  X)  COOO  "O 
l>»  t^CQ  OO  O^O^O  M  •-<  CM  CM  CO  CO  ^t*  *^~  >O  tO'O 

CM  CO    ^  O    *O  M    t^»  CO^'O    CMOO    ^O    I^COC^O 

C^-OO  C^  O  w  CM  CO  Th  IOVO  t^OO  Q\  O  t-i  CM  CO  Tf 
iO  vo  iOvO  'O'O'O'OOOOOO  C^  C^  t^  t>»  !>• 

M    M    CM    COvOQsCOOO    COO^'OMGO    ^O^O    CMOO 

cooo  cooo  cooo   •<tf-o>>ioOO  CM  tr^coo^Oto 

C^  1>-OO  OO^^OO'-iCMCMcOcOTt~'^}"lO'OO  Z 

MMMMMMCMCMCMCMCMCMCMCMCMCMCMCM 

.    _        ..      _  'Sl-I^COOt^  t) 

IHMMMMCMCMCMCMCMCMCMCMCMCMCMCMCM 
ON  O  *H  CM  CO  rj-  iO<O  t^OO  ON  O  M  CM  CO  Tf  IO^Q 

COr^CMO    M    >OO    1OGN'^}-C'>  Tj-00    COCO    COOO    COOO 

OOOOC^vCTiOOWMCMMCJcOCO-^-^iOiOOO  ^ 

O    M    CM    CO  Tf-  lOO    «>-OO    O  O    '-|    CM    CO  Th  iOO    1^00 
CMCMCMCMCMCMCMCMCMCMCOCOCOCOCOCOCOCOCO  g 

ioOO  coo>ilo^t'>-too  t^-CO   T}-CM  o  t^-  cooo  r^~ 

CO  l>»  O    ^  t>«  HH    lOQNCMO    M    iOO    *OO    M"GN  COOO 

8OMMMCMCMCMCOCOT)-'^-iO  iOO  VO  O    t^  t^ 
900099090999900900 

OOOOOOMCMCO  rfO  00    O    CM    Tj-  J>.  O    ^00 
ri-00    CM  O    O    ^t-OO    CM  O    O    ^00    CO  t>»  M    iO  O    ^00 

9999999999099999999 

**  CM  CO  ^"  iOO  t^-00  ^O  ^H  CM  CO^"iOO  t^OC-  O^ 


THE-WHITEFRIARS    PRESS,       LTD.      LONDON    AND    TONBRIDGE. 


fttsh 

QD77 
T64m 
1918 


Tognoli,  Edgardo.    42408 
Reagents  and  reactions. 
Translated  from  the  Ital- 
ian by  C.A.  Mitchell. 


